SHOULD HAVE

Should have

Should have can be used to express regret about the past – to wish that something in the past had happened in a different way:

I should have studied for my exam! (I didn’t study for my exams. I failed. Now I wish that the past was different.)

Should have can also be used to talk about something you expected to happen, but it didn’t happen (or it didn’t happen until later).

The letter should have arrived by now, but it hasn’t come yet. (I was expecting a letter, but it isn’t here). Here’s the bus! It should have been here twenty minutes ago. (The bus is late. It has just arrived).