Should is an auxiliary verb – a modal auxiliary verb. We use should mainly to:
* give advice or make recommendations.
* talk about obligation
* talk about probability and expectation
* express the conditional mood
Should is the past tense of shall in indirect speech.
* The officer said, ‘The scoundrel shall be given a good beating’
* The officer said that the scoundrel should be given@ a good beating.
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.
We used 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?
We use should most commonly to talk about what is the ideal or best thing to do in a situation:
There should be more public hospitals.