Speaking Boost · B2 · Lesson 21 of 50
Speaking Boost B2 · Block 5: Health and the Body

Why do we yawn?

Everyone yawns, even babies before birth, and scientists still do not fully agree on why. Learn to guess and draw conclusions with modals of deduction, and to talk about tiredness, boredom and attention.

1

Warm-up

5 min
1.1

Yawning and tiredness

Answer each question with 2–3 sentences.

  1. How often do you yawn?
  2. When do you feel most alert during the day?
  3. Do you yawn when other people yawn?
  4. What makes you drowsy?
  5. How much sleep do you need?
  6. What do you do when you are bored?
2

Words and phrases

12 min
2.1

New words

Read each word and the example. Then say a sentence about being tired.

2.2

Which word?

Choose the word that fits.

  1. I always when I'm bored in a meeting.
  2. Yawning is : when one person yawns, others often follow.
  3. After lunch I feel and want to sleep.
  4. Coffee makes me more .
  5. There are several about why we yawn.
  6. The smell of coffee can happy memories.
  7. We don't yet have enough to be sure.
  8. Scientists call it a because the cause is unclear.
2.3

Opposites and pairs

Choose the right answer, then press Check answers.

  1. drowsy =
  2. alert =
  3. contagious =
  4. a theory is an idea that
  5. to trigger = to
  6. empathy = understanding other people's
2.4

Useful phrases

Use these phrases to guess and draw conclusions.

  • He must be tired.Він, певно, втомлений.He must be tired; he keeps yawning.
  • She can't be bored.Вона не може нудьгувати.She can't be bored; she loves this topic.
  • It might be contagious.Можливо, це заразно.It might be contagious.
  • It could be because...Можливо, через те, що...It could be because the brain needs to cool down.
  • They may be asleep.Можливо, вони сплять.They may be asleep by now.
  • There has to be a reason.Має бути причина.There has to be a reason for it.
  • I'm sure that...Я впевнений, що...I'm sure that it's connected with sleep.
  • Nobody knows for certain.Ніхто не знає напевно.Nobody knows for certain why we yawn.
3

Read and react

8 min
3.1

The mystery of yawning

Read the text. Hover over the dotted words for help.

Why do we yawn?

Yawning is one of the most common things that humans do, yet nobody knows for certain why we do it. Even unborn babies yawn, and many animals yawn too.

Several theories exist. An old idea said that we yawn to take in more oxygen, but experiments have not supported it. A more recent idea is that yawning helps to cool down the brain: some studies suggest that people yawn more often when the air is warm, although the evidence is still limited. Another theory links yawning to changes of alertness, which could explain why we yawn when we are tired and also when we are bored or about to do something important.

Yawning is also contagious. Seeing or hearing someone yawn can make you yawn too. This usually begins in early childhood, and some researchers have linked it to empathy, although other studies have found only a weak connection. Dogs have been reported to catch human yawns as well.

So, if you see a person yawning, what can you conclude? They might be tired, they could be bored, or they may simply have seen another person yawn. The only safe conclusion is that it is still a mystery.

Did you yawn while reading this?

3.2

True or false?

  1. Even unborn babies yawn.
  2. Experiments have clearly proved that we yawn to get more oxygen.
  3. Some studies suggest that people yawn more often when the air is warm.
  4. Contagious yawning usually begins in early childhood.
  5. Scientists now fully understand why we yawn.
3.3

What do you think?

  1. Why do you think yawning is contagious?
  2. Is it rude to yawn in front of other people?
  3. What do you do to stay alert at work or study?
  4. Why do scientists find simple things like yawning hard to explain?
4

Grammar for speaking

10 min
4.1

Grammar for speaking

Modals of deduction (present)

Use must for strong certainty, can't for strong certainty that something is not true, and may, might or could for possibility. For actions in progress, use modal + be + -ing.

He must be tired. She can't be bored; she loves this topic. They might be asleep. He could be yawning right now.

Degrees of certainty

Adverbs show how sure you are: definitely, probably, possibly, perhaps. They go after be and before a main verb. Perhaps goes at the start of a sentence.

He is definitely tired. She'll probably sleep. Perhaps it's connected with sleep.

Block 5 preview

Grammar you will use in this block.

modals of deduction (L21) · first conditional, unless (L22) · second conditional, wish (L23) · advice: should, had better (L24) · conditionals and advice review (L25)

Common mistakes: must be, can't be, might be + adjective or -ing. ✗ He must tired → He must be tired. ✗ She can't being bored → She can't be bored.

4.2

Choose the right form

  1. He keeps yawning. He
    tired.
  2. She loves this topic, so she
    bored.
  3. They
    asleep, but I'm not sure.
  4. He
    right now.
  5. That
    true!
  6. It
    because the room is warm.
  7. She is
    tired.
  8. it's connected with sleep.
4.3

Fix the mistake

Each sentence has one mistake. Type the correct words.

  1. He must tired. →
  2. She can't being bored. →
  3. They might to be asleep. →
  4. He is probable tired. →
  5. It must is because of the heat. →
  6. He could be sleep now. →
4.4

Talk about it

Answer in detail. Use must, might, could and can't to guess.

  1. Why do you think people yawn?
  2. Tell me about a time when you couldn't stop yawning.
  3. Who in your family must be the sleepiest? Why?
  4. What can you tell about a person from the way they look?
  5. How do you try to stay awake when you are tired?
  6. Do you believe that yawning is contagious? Why?
5

Three people who yawn and a short talk

8 min
5.1

Three people who yawn

Three people yawn a lot. Make guesses about why. Who must be the most tired? Who can't be bored? What advice would you give each one?

Person 1

Mark, 35

  • Works night shifts
  • Yawns all day
  • Drinks four coffees
  • Might be short of sleep
Person 2

Dr Lee, 48

  • Studies sleep
  • Believes yawning cools the brain
  • Admits the evidence is limited
  • Could be right or wrong
Person 3

Zoe, 8

  • Yawns when others yawn
  • Is kind to her friends
  • Can't stay awake in class
  • Must be growing fast
5.2

Mini-talk: tiredness and attention

Your teacher will time you.

  1. Plan for one minute, then speak for one or two minutes.
  2. Part 1: guess why a person you know is tired (must, might, can't).
  3. Part 2: a theory you know and how sure you are about it.
  4. Part 3: how you try to stay alert.
2:00
6

Personal questions

10 min
6.1

Part I: Me

  1. How often do you yawn?
  2. When do you feel most alert?
  3. What makes you drowsy?
  4. Do you yawn when others do?
  5. How much sleep do you need?
  6. What do you do when you're bored?
  7. Do you drink coffee to stay awake?
  8. What helps you stay focused?
6.2

Part II: Other people

  1. Who in your family yawns the most?
  2. Who is never tired?
  3. Who falls asleep in front of the TV?
  4. Who works night shifts?
  5. Who do you know that sleeps very little?
  6. Who gets bored easily?
6.3

Part III: A bit deeper

  1. Should schools start later?
  2. Is sleep more important than work?
  3. Is it rude to yawn in public?
  4. Can we trust scientific theories that change?
  5. Do we sleep enough nowadays?
7

Roleplay

12 min
7.1

Guessing the reason

You

Friend

A friend (your teacher) looks very tired. Talk to him:
  • notice how he looks
  • guess why, using must and might
  • ask what he did last night
  • suggest what to do
Speak for at least 2 minutes in total. Use modals of deduction.
Your teacher

Friend

Says things like:
  1. I didn't sleep well.
  2. What do you think the reason is?
  3. I've been working a lot.
  4. I'll try to rest.
7.2

Explaining a theory

You

Presenter

You explain a scientific theory to a friend (your teacher):
  • say what the theory is
  • say how sure you are
  • give an example
  • say what we don't know
You do most of the talking. Use: It might be... · It could be because... · Nobody knows for certain...
Your teacher

Friend

Says things like:
  1. Why do we yawn?
  2. Is that proven?
  3. Can you give an example?
  4. So what is the answer?
8

Homework

at home

Your homework score

Do all four exercises, then press Check all homework. Correct answers will appear next to your mistakes.

– / 30
H1

Complete with a word

yawncontagiousdrowsyalerttheoriestriggerevidencemystery
  1. I always when I'm bored in a meeting.
  2. Yawning is : when one person yawns, others often follow.
  3. After lunch I feel and want to sleep.
  4. Coffee makes me more .
  5. There are several about why we yawn.
  6. The smell of coffee can happy memories.
  7. We don't yet have enough to be sure.
  8. Scientists call it a because the cause is unclear.
H2

Choose the correct form

  1. She's been working all night. She exhausted.
  2. He at home; his car isn't here.
  3. They late, but I'm not sure.
  4. She now.
  5. It a mistake.
  6. He is asleep.
  7. he's busy.
  8. That true!
H3

Correct or incorrect?

Decide if each sentence is grammatically correct.

  1. He must be tired; he keeps yawning.
  2. He must tired.
  3. She can't be bored.
  4. They might to be asleep.
  5. It could be because the room is warm.
  6. He is probable tired.
  7. He is definitely tired.
H4

Match the two halves

  1. He must be tired;
  2. She can't be bored;
  3. It might be
  4. It could be because
  5. They may be
  6. There has to be
  7. Nobody knows for certain

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© Yevheniia Kolesnykova, Academy of Languages. All rights reserved. No copying or reuse without written permission.