Be expressions (be able to, be due to)

from English Grammar Today

Be about to

Be about to is used to talk about things which are going to happen very soon:

I’m about to eat. Can I phone you back?

It is often used with just:

We’re just about to set off for a walk. Do you want to come?

When used in the past, be about to can refer to things that were going to happen but didn’t:

I was about to complain but he came over and apologised.

We don’t use be about to with time expressions:

I was about to call you.

Not: ~~I was about to call you in ten minutes~~.

Be able to

Abilities

Be able to is like can. We use it to talk about abilities. We often use it in places where it is not possible to use can. For example, it isn’t possible to use can after another modal verb:

She won’t be able to concentrate.

Not: ~~She won’t can concentrate~~.

He should be able to work in a team.

Not: ~~He should can work in a team~~.

Be able to is a more formal alternative to can:

I am very sorry but I am not able to give you that information. (or, less formal: I cannot give you that information.)

Past achievement: could or was/were able to?

We usually use was/were able to, not could to talk about past achievements in affirmative clauses. This is because they are facts, rather than possibilities:

Only one person was able to beat the record.

Not: ~~Only one person could beat the record~~.

We use couldn’t or, more formally, wasn’t/weren’t able to in negative clauses:

We weren’t able to finish the marathon in under four hours. (or We couldn’t finish the marathon …)

Be due to

Be due to is used to talk about things that are expected or planned to happen at a certain time. We often use it with a time expression:

Are you due to hand in homework today?

The train is due to arrive at Glasgow Central at 12:12.

Be likely to

Be likely to is used to talk about how probable things are:

Are parents who have a lot of money likely to spoil their children?

It is often used to make comparisons with words like more and less:

I think men are more likely to spend a lot of money on food than women are.

A:
I liked Budapest as well.
B:
Yeah. I’m probably less likely to go back there than to Prague.

We also use it’s likely followed by that + clause:

It’s likely that sales will rise.

We form the negative of be likely to and be likely that either with not or with unlikely. Unlikely is more formal:

The company is not likely to make a profit in the second half of the year.

People are unlikely to listen to him now because they know he lied.

Be meant to

Be meant to is used to talk about what is desirable, expected or intended:

A:
It looks green to me.
B:
Oh, is it meant to be a different colour?

It was meant to be like a quiz and we were all in different teams and there was meant to be a fantastic prize.

Be supposed to

Be supposed to is used to talk about obligations and arrangements:

Where were you? You were supposed to be at the party!

You’re supposed to have an hour for lunch. That’s the law.

It’s also used to talk about people’s expectations or beliefs about something:

[talking about some medicine]

A:
Take some of this.
B:
What’s it supposed to do? (What does it do to you?)

And then I’m gonna get a train over to Brussels which takes all day as well. It’s supposed to be a nice route with forests and mountains and things. (gonna represents ‘going to’, as it is pronounced in informal speaking.)