（尤用于纠正别人）应该，应当used to show what is right, appropriate, etc., especially when criticizing sb's actions
You shouldn't drink and drive.
He should have been more careful.
A present for me? You shouldn't have !(= used to thank sb politely)
（提出或征询建议）该，可以used for giving or asking for advice
You should stop worrying about it.
Should I call him and apologize?
I should wait a little longer, if I were you .
‘She doesn't think she'll get a job.’ ‘She should worry, with all her qualifications(= she does not need to worry) .’
（表示预期）应该会，可能used to say that you expect sth is true or will happen
We should arrive before dark.
I should have finished the book by Friday.
The roads should be less crowded today.
（表示与预期相反）本应，本当used to say that sth that was expected has not happened
It should be snowing now, according to the weather forecast.
The bus should have arrived ten minutes ago.
（与 I 或 we 连用代替 would，表示虚拟结果）就将used after or instead ofwould for describing what you would do if sth else happened first
If I were asked to work on Sundays, I should resign.
（表示可能）假如，万一used to refer to a possible event or situation
If you should change your mind, do let me know.
In case you should need any help, here's my number.
Should anyone call(= if anyone calls) , please tell them I'm busy.
（在间接引语中用作 shall 的过去时）used as the past form ofshall when reporting what sb has said
He asked me what time he should come.(= His words were: ‘What time shall I come?’)
I said (that) I should be glad to help.
（用于 that 引导的、表示建议或安排的从句中）used afterthat when sth is suggested or arranged
She recommended that I should take some time off.
In order that training should be effective it must be planned systematically.
（用于许多表示感情的形容词后的 that 从句中）used afterthat after many adjectives that describe feelings
I'm anxious that we should allow plenty of time.
I find it astonishing that he should be so rude to you.
（与 I 和 we 连用，表示客气地请求）used with and in polite requests
I should like to call my lawyer.
We should be grateful for your help.
（与 I 和 we 连用，表示没有把握）used with and to give opinions that you are not certain about
I should imagine it will take about three hours.
‘Is this enough food for everyone?’ ‘ I should think so .’
‘Will it matter?’ ‘ I shouldn't think so .’
（表示十分赞同）used for expressing strong agreement
‘I know it's expensive but it will last for years.’ ‘ I should hope so too! ’
‘Nobody will oppose it.’ ‘ I should think not! ’
why, how, who, what ~ sb/sth do
（表示拒绝、恼怒或惊奇）used to refuse sth or to show that you are annoyed at a request; used to express surprise about an event or a situation
Why should I help him? He's never done anything for me.
How should I know where you've left your bag?
I got on the bus and who should be sitting in front of me but Tony!
（表示假如对方看见或经历某事物，一定会感兴趣或吃惊）真该，真应当used to tell sb that sth would amuse or surprise them if they saw or experienced it
You should have seen her face when she found out!