should

Children should be seen and not heard.

something that you say which means that children should be quiet. I can't stand all that shouting. Children should be seen and not heard, in my opinion.

See also: hear, seen

on no account must/should someone do something (formal)

if you tell someone that on no account must they do something, you mean that they must never, for any reason do that thing. On no account must the contents of this document be shown to any other person.

See also: account, must

You can talk! (British, American & Australian, informal, American, informal)

something that you say when someone criticizes another person for doing something that they do themselves. 'He's a terrible driver.' 'You can talk!' And you're telling me I'm lazy? You should talk!

See also: can, talk

You should be so lucky! (informal)

something that you say in order to tell someone that what they want is not likely to happen. A pay increase? You should be so lucky!

See also: lucky