Draw it, then say it: defining relative clauses for describing diagrams

Q: How do you use defining relative clauses?

Use a defining relative clause to say exactly which person, thing or place you mean : This is the service that sends payout alerts. Without the clause, the listener doesn't know which service. It comes right after the noun, with no commas, and starts with who , which , that , where or whose : Merchants are the shop owners who use the app.

Q: When do you use who, which or that?

Use who for people, which for things, that for both : the tech lead who drew it , the box which handles payout alerts , the system that takes card payments . In clauses like these, American English uses that for things more often than which , but both are correct. When you aren't sure, that is the safe choice in a defining clause, for a person or a thing.

Q: When can you leave out "that", "who" or "which"?

You can leave it out when a new subject follows it , because then it's the object of the clause: the alerts (that) merchants get , the diagram (that) our lead drew . When a verb follows, the pronoun is the subject and must stay: the service that sends alerts , not the service sends alerts . A sorting task in Draw it, then say it on edio.ai splits eight phrases this way.

Q: Is it "who" or "whose"?

Use whose + a noun for something that belongs to someone , and who for the person who acts: a merchant whose alert doesn't arrive , but a merchant who uses the app . Whose replaces his , her or their : This is a merchant. Her payout alert didn't arrive. becomes This is the merchant whose payout alert didn't arrive. Don't mix it up with who's , short for who is .

Q: Can you use "who" for things?

No, who is for people , so a service, an app or a database takes that or which : the service that handles payments , not the service who handles payments . The reverse mistake happens too: the person which drew the diagram should be the person who drew the diagram . The chat in Draw it, then say it , a B1 English for IT lesson on edio.ai, offers both errors as wrong replies.

Q: Is it "the app that we build" or "the app that we build it"?

It's the app that we build , with no extra it , because that already stands for the app. The same goes for them and there : the services that the phone companies run , not …run them ; the database where we keep logs , not …keep logs there . Since that is the object here, you can also drop it: the app we build .

Q: How do you describe an architecture diagram in English?

Start with the big picture, then zoom in box by box: say where each box is, what it does and how it links to the others. On the left, there's the merchant. The app connects to the API. This is the service that sends alerts. This arrow shows where the data goes. End with a check: Does that make sense? These lines come from the phrase bank of Draw it, then say it on edio.ai.

Q: What does "the big picture" mean?

The big picture means a simple overview without the small details : what a system is for, who uses it and its main parts. At work, people ask for it before the details: Can you give us the big picture in two minutes? In a C4 diagram, level 1 is the big picture, with the whole system as one box. To look closer at one part, you zoom in .

Q: How do I teach defining relative clauses to B1 adults?

Give learners things to identify , because a defining clause answers the question Which one? Draw three boxes and ask which one sends alerts. Then join two sentences on the board, cross out the it or them , and show that that can go only when a new subject follows. Professionals can describe their own system; others can draw how a support question gets an answer.

Q: How do you practice explaining a diagram with an in-company group?

Hand out role cards and set a two-minute timer : each learner draws three to five boxes of a system they know, explains every box and arrow, and each listener asks one question. Give each role a different listener, such as a new developer, a manager or a support agent. The open boxes in Draw it, then say it , a B1 English for IT lesson on edio.ai, hold six such role cards.

Learners describe software with defining relative clauses in this B1 English for IT lesson plan built around an architecture diagram.

Grammar: Who or that for people, which or that for things, where for places and whose + noun, as in the service that sends alerts, and when the pronoun can go.
Topic: Explaining an architecture diagram to the support team of a fictional payments startup, with words such as container, component, notification service and external system.
Activities: The story of the C4 model and a page about a diagram to read, a two-minute explanation, self-checking drills, a chat and role cards, then a description to write and record.

What's inside

Chapter 1Warm-up: Boxes and Arrows
- PictureUnlock
- Spin the wheel and answerSpin the wheelUnlock
- Study the words for describing a diagramVocabularyTry it
- Look at the pictures and choose the wordChoose by pictureUnlock
Chapter 2The Story: A Map You Can Zoom
- Read the story of the C4 modelArticleUnlock
- Choose the correct answer about the storyQuizUnlock
Chapter 3At Work: The App on One Page
- Read Kenji's page about the merchant appArticleUnlock
- True or false? Check Kenji's pageTrue or falseUnlock
- Match each box with its descriptionMatchUnlock
Chapter 4Listen: Two Minutes, One Diagram
- Listen to Kenji explain the diagram to FatimaListeningTry it
- Transcript, for the teacherUnlock
- Choose the correct answer about the callQuizUnlock
Chapter 5Grammar: The Box That Sends Alerts
- Study the scheme: relative clausesGrammar schemeTry it
- Choose the correct option to complete each sentenceChoose the optionTry it
- Join the two sentences: fill in the gapsFill in the gapsUnlock
- Sort the phrases: can you leave out “that”?Sort into columnsUnlock
- Fill in the gaps with the correct relative word: Kenji's refund diagramFill in the gapsUnlock
Chapter 6Speak Up: Explain Your Diagram
- Choose the right replies to FatimaChatTry it
- Open a box: take a role and explain a diagramOpen the boxUnlock
Chapter 7Homework: Draw It, Then Say It
- Read your phrase bankReal-life documentTry it
- Do you remember? Choose the correct answerQuizUnlock
- Is the sentence correct? True or falseTrue or falseUnlock
- Find the matching pairs: words and meaningsMemory gameUnlock
- Write a description of a simple diagramWriting, checked by the teacherUnlock
- Record yourself explaining your diagramSpeaking, checked by the teacherUnlock

Architecture diagram vocabulary

12 words and phrases from the lesson, each with a picture and audio in edio.

+9 more with pictures and audio in the lessonMore words

a component
a database
a notification service
an external system
an arrow
connect to
send data to
zoom in
handle

Grammar: defining relative clauses

A defining relative clause tells the listener which person, thing or place you mean, so the sentence needs it: This is the service that sends alerts. On an architecture diagram, where every box needs a name and a job, learners choose the relative word by what they describe and join two sentences into one.

Relative clauses: say which box you mean

Who, which, that, where and whose join two ideas: the service that sends alerts, the place where we keep crash reports.

Who, which, that, where or whose?

Who or that describes a person, which or that a thing, where + subject + verb a place, and whose + noun something that belongs to someone: Merchants are the shop owners who use the app. This is the database where we keep crash reports.

You describe	Use	Example
a person	who / that	Merchants are the shop owners who use the app.
a thing	which / that	This is the service that sends payout alerts.
a place	where + subject + verb	This is the database where we keep crash reports.
something that belongs to someone	whose + noun	A merchant whose alert doesn't arrive can check the app.
a person or thing as the object	who / which / that can go	These are the apps (that) we build.

Two sentences become one

The relative word takes the place of it, them or there in the second sentence, so those words disappear: This is the service. It sends alerts. becomes This is the service that sends alerts, never that it sends alerts.

sentence 1who / which / that / where / whosesentence 2 without it / them / there / her…

This is the service. It sends alerts. → This is the service that sends alerts.

We drew a diagram. Fatima uses it. → Fatima uses the diagram (that) we drew.

This is the database. We keep logs there. → This is the database where we keep logs.

One sentence for every box

Each box of a diagram gets a clause that says what it does or what happens there: The push services are external systems which deliver alerts to phones. The payout screen is the place where the real status is.

Kestrel Pay is the system that takes card payments.a thing: that or which
The push services are external systems which deliver alerts to phones.a thing: which or that
Fatima is the support lead who brings merchants' problems to the team.a person: who or that
The payout screen is the place where the real status is.a place: where
Merchants whose alert doesn't arrive can still see the payout.possession: whose + noun
The merchant app is the system (that) our team builds.an object: that can go

When can that go?

Look at the word after the pronoun. A verb means the pronoun is the subject, so it stays: the service that sends alerts. A new subject means it's the object, so it can go: the diagram (that) Kenji drew.

When can that go?

Look at the word after who, which or that. If it's a verb (sends, uses), the pronoun is the subject: keep it. If it's a new subject (we, Kenji, merchants), the pronoun is the object, and you can leave it out: the diagram (that) Kenji drew. Who is for people, which for things, and that for both.

Typical mistakes

the service who handles payments
the service that / which handles payments
who is only for people
the person which drew the diagram
the person who / that drew the diagram
which is only for things
the API which it sends data to the app
the API which sends data to the app
which takes the place of it: no extra it
the service which they own it
the service (which) they own
no extra it or them at the end

More lessons on this grammar: Relative clauses lessons and exercises

Try the defining relative clauses exercises

Try them yourself: these are the same exercises your students do in edio.

What's in the lesson

12 auto-checked exercises
3 games
2 teacher-checked tasks
1 real-life document
2 articles
1 grammar scheme
1 set of word cards
1 audio clip
1 picture
1 transcript

The main objectives of this lesson are to:

say which box you mean with who, which, that and where: This is the database where we keep crash reports.
show possession with whose + noun: Merchants whose alert doesn't arrive can still see the payout.
drop the object pronoun, but never add an extra it or them: the apps (that) we build, not the apps that we build them
explain an architecture diagram to a colleague in two minutes, from the big picture to each box

Lesson 15 closes unit 5 of English for IT B1 · Inside the Team, How it works, whose goal is to explain a system with a simple diagram. It brings the A2.2 relative clauses with which, that, who and where to work, adds whose, and reviews the unit's time clauses and passive. A diagram is a set of boxes, and a defining clause names each one: the box that sends alerts.

Students spin a wheel about diagrams and learn twelve words with pictures and audio, from an architecture diagram to zoom in. The story is Simon Brown's C4 model, which draws software like a map with four zoom levels, where a container is an app or a data store, not a Docker container. Kenji's one-page description of a payments app's diagram follows, and in an AI-voiced call he explains it to the support lead in two minutes.

Four self-checking drills follow the scheme: relative words to choose, sentence pairs to join into one, phrases to sort by whether that can go, and a refund diagram to complete. Students then answer the support lead's questions in a chat and take role cards, from tester to DevOps engineer, to explain their own diagram in two minutes.

Homework opens with the phrase bank, then a unit review, a true-or-false check and a memory game that check themselves. Students then draw a diagram of a system they know, describe it for a new colleague and record the explanation; the teacher reviews both.

Grammar:: defining relative clauses · who, which, that, where, whose
Topic:: architecture diagrams · the C4 model · explaining systems

Teaching tips

Let students draw while they listen: from the call alone, they sketch the merchant, the two apps, the API, the box with the bell and the can, then compare sketches with a partner.
Draw a system the whole class knows, such as a food delivery app or the school's website, and have students name each box with the part that… or the place where…
Time the two minutes with the role cards: a phone timer keeps explanations short, and each listener's one question shows whether the big picture came across.
For one-to-one professionals, use their real architecture: they sketch it first, and every box they describe becomes a relative clause to polish together.

Liked it?

Teach the whole lesson in edio

25 exercises in 7 chapters, ready to teach. edio is an online platform for language schools and teachers: ready-made interactive lessons, live classes, homework and student progress in one place.

Start a free trial
7 days, no credit card.
Open the lesson
Find it in the library of 621 ready lessons. Teach it as it is, or copy any chapter into your own lessons.
Teach it live or as homework
Students work in their own accounts, in sync with you during the lesson, and the practice exercises check themselves.

Teach it free for 7 days

The whole course: English for IT B1 · Inside the Team

24 lessons at B1 for people who build, test or run software, in American English. Learners follow Iryna, a junior developer, through her first year at Kestrel Cloud, a fictional payments startup: standups, tickets, code review, chats across time zones and job interviews. Each lesson is built around a true story from software history.See the course

Unit 1 Hello, team
roles, stacks and first days: the present simple, the present perfect with for and since, question forms
Unit 2 The daily standup
updates and blockers: the present simple and continuous, just, already and yet, have to and need to
Unit 3 Bugs and tickets
clear bug reports: the past continuous, imperatives and the zero conditional, quantifiers
Unit 4 Code review
kind, useful comments: -ed and -ing adjectives, modals for suggestions, the first conditional
Unit 5 How it works
explaining systems step by step: time clauses, the passive, relative clauses
1. Lesson 13What happens when you type a URL?Time clauses with as soon as, until and once
2. Lesson 14How is a barcode read?The present and past simple passive
3. Lesson 15 · you're hereDraw it, then say itDefining relative clauses
Unit 6 Remote and async
chat, email and time zones: polite requests, future forms, the present perfect continuous
Unit 7 Users and clients
user stories and plain explanations: verb + to or -ing, reported speech, comparisons
Unit 8 Your next job
resumes and interviews: used to, the past perfect, the second conditional

Questions about this lesson

How do you use defining relative clauses?

Use a defining relative clause to say exactly which person, thing or place you mean: This is the service that sends payout alerts. Without the clause, the listener doesn't know which service. It comes right after the noun, with no commas, and starts with who, which, that, where or whose: Merchants are the shop owners who use the app.

When do you use who, which or that?

Use who for people, which for things, that for both: the tech lead who drew it, the box which handles payout alerts, the system that takes card payments. In clauses like these, American English uses that for things more often than which, but both are correct. When you aren't sure, that is the safe choice in a defining clause, for a person or a thing.

When can you leave out "that", "who" or "which"?

You can leave it out when a new subject follows it, because then it's the object of the clause: the alerts (that) merchants get, the diagram (that) our lead drew. When a verb follows, the pronoun is the subject and must stay: the service that sends alerts, not the service sends alerts. A sorting task in Draw it, then say it on edio.ai splits eight phrases this way.

Is it "who" or "whose"?

Use whose + a noun for something that belongs to someone, and who for the person who acts: a merchant whose alert doesn't arrive, but a merchant who uses the app. Whose replaces his, her or their: This is a merchant. Her payout alert didn't arrive. becomes This is the merchant whose payout alert didn't arrive. Don't mix it up with who's, short for who is.

Can you use "who" for things?

No, who is for people, so a service, an app or a database takes that or which: the service that handles payments, not the service who handles payments. The reverse mistake happens too: the person which drew the diagram should be the person who drew the diagram. The chat in Draw it, then say it, a B1 English for IT lesson on edio.ai, offers both errors as wrong replies.

Is it "the app that we build" or "the app that we build it"?

It's the app that we build, with no extra it, because that already stands for the app. The same goes for them and there: the services that the phone companies run, not …run them; the database where we keep logs, not …keep logs there. Since that is the object here, you can also drop it: the app we build.

How do you describe an architecture diagram in English?

Start with the big picture, then zoom in box by box: say where each box is, what it does and how it links to the others. On the left, there's the merchant. The app connects to the API. This is the service that sends alerts. This arrow shows where the data goes. End with a check: Does that make sense? These lines come from the phrase bank of Draw it, then say it on edio.ai.

What does "the big picture" mean?

The big picture means a simple overview without the small details: what a system is for, who uses it and its main parts. At work, people ask for it before the details: Can you give us the big picture in two minutes? In a C4 diagram, level 1 is the big picture, with the whole system as one box. To look closer at one part, you zoom in.

How do I teach defining relative clauses to B1 adults?

Give learners things to identify, because a defining clause answers the question Which one? Draw three boxes and ask which one sends alerts. Then join two sentences on the board, cross out the it or them, and show that that can go only when a new subject follows. Professionals can describe their own system; others can draw how a support question gets an answer.

How do you practice explaining a diagram with an in-company group?

Hand out role cards and set a two-minute timer: each learner draws three to five boxes of a system they know, explains every box and arrow, and each listener asks one question. Give each role a different listener, such as a new developer, a manager or a support agent. The open boxes in Draw it, then say it, a B1 English for IT lesson on edio.ai, hold six such role cards.

What's good homework for practicing defining relative clauses?

Good homework has learners describe a diagram they drew themselves, one clause per box: On the left are the members who book classes. The booking service connects to a database where we keep every booking. In Draw it, then say it on edio.ai, a review quiz, a true-or-false check and a memory game come first and check themselves; then students write the description and record it for the teacher.

Are there interactive exercises for defining relative clauses?

Yes: self-checking choices and chat role-plays show at once whether a learner picked who, which, where or whose. Without an account, this page plays four parts of Draw it, then say it, a B1 English for IT lesson on edio.ai: a call in which a tech lead explains a diagram to support, a drill to complete each sentence, a chat answering the support lead's questions, and the phrase bank. Other exercises are locked.

Unlock full lesson

About this lesson

What's inside

Architecture diagram vocabulary

Grammar: defining relative clauses

Who, which, that, where or whose?

Two sentences become one

One sentence for every box

When can that go?

Typical mistakes

Try the defining relative clauses exercises

What's in the lesson

The main objectives of this lesson are to:

Teaching tips

Teach the whole lesson in edio

Start a free trial

Open the lesson

Teach it live or as homework

The whole course: English for IT B1 · Inside the Team

Unit 1 Hello, team

Unit 2 The daily standup

Unit 3 Bugs and tickets

Unit 4 Code review

Unit 5 How it works

Unit 6 Remote and async

Unit 7 Users and clients

Unit 8 Your next job

Questions about this lesson

Teach this lesson with your students