Modals of permission, obligation and necessity

We ____________ at 8:45, but few people arrive before 9:00.

• 're supposed to start

• must start

• both

Answer explanation

It is not technically permitted, but some people do it.

Unless you're meeting clients, you ____________ formally.

• don't have to dress

• don't need to dress

• both

Answer explanation

Have to and need to are the same.

You _____________ the application soon. The deadline's at 4pm.

• 'd better send

• must send

• both

Answer explanation

There is no obligation to send the application, therefore must doesn't make sense here.

However, there may be negative consequences if you do not, e.g. it will not be accepted.

You ____________ told the client we'd deliver on Friday. There's no chance of that happening.

• shouldn't have told

• can't have told

• both

Answer explanation

Can't have told means that you are sure this didn't happen.

Shouldn't have told is used to criticise a past action, i.e. you told the client but I think that was the wrong thing to do.

We __________ to finish the report. They've just extended the deadline.

• ought not to hurry

• needn't have hurried

• both

Answer explanation

Ought not to is used to give advice, which doesn't make sense in this context.

Needn't have hurried means that they hurried to finish the report but it wasn't necessary in the end.

You ______________ to smoke anywhere in this building.

• are not permitted

• aren't allowed

• both

EU residents ___________ a visa to travel within the Euro zone.

• needn't get

• don't need to get

• both

Answer explanation

Needn't is only used to refer to specific situations, not general ones.

E.g. You needn't bring a coat. It's going to be quite warm this afternoon.

Don't need/have to can be used for both general and specific situations.

You ___________ bring your laptop to the meeting today.

• don't have to

• needn't

• both

You _____________ late again. The boss will go through the roof!

• ought not to be

• 'd better not be

• both

Answer explanation

Here there is a negative consequence for the person's lateness so had better makes the most sense.

We _____________ to access social media site from work computers.

• aren't allowed

• aren't able

• both

Answer explanation

We often use be able to interchangeably with be allowed to in order to express what is possible or permitted.

E.g., "Harry isn't able to drink yet. He's only 17."

Here able doesn't refer to physical ability but rather to lack of permission.