Modal Verbs - GE 9 - 12

MODAL VERBS

Deduction in the present and the past, use:

Must

Could

Might

May

Can’t

Modals	Use when
must	We believe something is true.
Could, might, may	We think something is possibility true.
Can’t	We believe something isn’t true.

Definitely true or not true, don’t use modal verbs.

I had it when I left the café because I called mum.

OK, so you didn’t leave it in the café.

Deduction in the present

Use	Formula
Deduction about state in the present	Modal verb + infinitive It might be in the bathroom. Yes, of course, but it must be switch off.
Deduction about something happening now.	Modal verb + be + verb + ing But someone might be using it to phone Aussie.

Deduction in the past

Use	Formula
Deduction about state or a completed action in the past.	Modal verb + have + past participle Or someone could have taken it from your bag. So you may have left it on the table. You cannot have left in the bar. The guy in the club must have stolen it.
Deduction about a longer action in the past.	Modal verb + have + been + verb + ing He might have been waiting a chance to steal my phone.

Tips:

You can also use couldn’t instead of cannot to make deduction in the past.

Past form and related verbs

Past Modals Formula	Use
Could have + past participle	To say something was possible in the past, but didn’t happen. They could have decided to leave all their money to their children, but they haven’t.
Should have + past participle	To criticize people behaviour in the past. Some people felt she should have left at least some of that to her children. Tips: Also use should have + past participle to talk about regrets. I should have listened to your advice.
Would have + past participle	To imagine something in the past that didn’t happen. Many people would have reacted differently. Tips: We often use as part of a third conditional. If you told me about the meal, I would/could have gone.
Needn’t have + past participle	To talk about things people did in the past that weren’t necessary. She needn’t have given it all away. = she did give it all away, but this wasn’t necessary.
Didn’t need + to	To talk about things people didn’t do in the past because they weren’t necessary. She decided that her daughters would be alright, and she didn’t need to leave them her money. = she didn’t leave them her money because she thought it wasn’t necessary. To talk about people did in the past, but weren’t necessary. He didn’t need to wait for her, so he went straight home. = he didn’t wait for her. He didn’t need to wait for her, but he had nothing better to do. = he waited for her.
Could	To talk about a general ability in the past. My sister could speak three languages before she was ten. She could give away millions of pounds every year. Tips: Usually use could with verbs of the sense (see, hear, etc). We could see the take out of our hotel window.
Was / were able to	To talk about ability at one specific time in the past. Due to her past wealth, she was able to leave $ 1000 to her dog. Similar meaning to managed to He was able to manage to build his business empire.
Couldn’t wasn’t able to weren’t able to	In negative forms, can both be used in all situation, although couldn’t is more common. I couldn’t find my wallet = I wasn’t able to find my wallet.