4A - Present and past speculation/deduction

• Engels
• Middelbare school
• havo, vwo
• Leerjaar 3

Modals of deduction and probability

Modals of deduction and probability

- If you’re certain that something is true, based on evidence --> must

There must be more planets in the universe than we’re aware of.

- If you’re certain that something is not true, based on evidence --> can’t

Similar life forms to our own can’t exist in our solar system.

- If you are not sure whether something is true --> might / may / could

Life could exist elsewhere in the universe.

- To increase the possibility --> could / may / might followed by well

They might well be planning a new space programme now.

Not 100% certain

may (not) = in Dutch "misschien". There is a reasonable chance that it will happen. May is rather formal and not used very often.

could = in Dutch "zou kunnen". There is a good 

chance that it will happen; perhaps 50-50%

might (not) = in Dutch "heel misschien". There is only a

slim chance that it will happen

100% certain

must - when you are 100% sure 

that something will happen.

can't/couldn't - when you are 

100% sure that something will 

not happen 

Practice!

On the next slides you're going to rewrite 

sentence using the modal verbs. 

Take the following steps:

step 1: Is it a present or past sentence?

              present --> modal + infinitive

              past --> modal + have + past participle

step 2: find the main verb

Example: rewrite using MUST

"I'm sure it's a lion"

step 1: present 

              (modal + infinitive)

step 2:  is (to be)

It must be a lion.

Rewrite using MUST
"I'm sure it's cold out"

Rewrite using MIGHT
"It's possible it escaped from the zoo."

Rewrite using COULD

"Perhaps he's very hungry by now."

Rewrite using COULD

"It's possible it was somebody's pet."

Rewrite using MAY

"Perhaps it grew too big."

Rewrite using CAN'T

"I'm sure it isn't a lion."

More examples? 

Check out the rest of the video!

Your teacher: You ... hand in your homework tomorrow or you will fail.

1. can
2. have to
3. must
4. should

You ... visit your aunt in hospital.

1. must
2. should
3. have to
4. can

She isn't answering the phone. She ... be out.

1. must
2. can't
3. might

They... be Spanish, they're speaking Portuguese.

1. must
2. can't
3. might

He ... have a job interview today - he's waiting to hear from the company.

1. must
2. can't
3. might

4A

Make exercise 1, 2, 3, 9, 10, 11, 12, 5, 6, 7.