Should and shouldn’t

Should come first (after the subject and before another verb) in the verb phrase:

Should comes first in the verb phrase (after the subject and before another verb):

I should go home now.

Should cannot be used with another modal verb:

It should probably be sunny at that time of year.

Not: It should may be sunny … or It may should be sunny …

Negative form:

The negative form of should is shouldn’t. We don’t use don’t, doesn’t, didn’t with should:

There shouldn’t be many people at the beach today.

We use the full form should not in formal contexts or when we want to emphasis something:

We should not forget those who have given their lives in the defence of freedom.

Question form:

To make inquiries, the subject and should switch positions.

We don’t use do, does, did:

Should I turn on the air conditioning?

Not: Do I should I turn on the air conditioning?

Shouldn’t you be studying now?

We use should and shouldn’t in question tags:

I shouldn’t have told her that, should I?

They should be getting back on Sunday, shouldn’t they?