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 …
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.
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?