should have

Should have looks back at the past and says what would have been better. With I or we, it is usually a regret: you are sorry about it. With other people, it is often a criticism.

The verb after have is the past participle (gone, done, told), never the base verb or the past simple.

Shouldn't have

Shouldn't have says that something happened and it was a mistake.

Should've in speech

In speech, should have sounds like should've. You can write should've in messages, but never should of.

Questions

Put should before the subject.

Should or should have

Should + base verb gives advice about now or the future. Should have + past participle is about the past, when it is too late to change.

Common mistakes

• × I should left earlier. → I should have left earlier.
• × You should have came yesterday. → You should have come yesterday.
• × We should of asked. → We should have asked.