should
//ʃʊd//
modal verb
1
Used to indicate obligation, duty, or correctness, typically when criticizing someone's actions or giving advice.
You should apologize to her.
2
Used to indicate what is probable or expected.
They should arrive by noon.
3
Used in conditional clauses expressing what would happen or what one would do under certain circumstances.
If anyone called, I should be grateful if you could take a message.
4
Used to express a polite request or suggestion.
I should like to make a suggestion.
5
Used to express a tentative opinion or desire.
I should think he's about 40 years old.
6
Used in subordinate clauses after certain verbs, adjectives, and nouns to express purpose, necessity, or possibility.
It is important that he should understand the rules.