- I don't know you are coming, so I don't invite some friends in

=> If I had known you are coming, I would have invited some friends in.
- I can't look the word up because I haven't got a dictionary

=> If I had had got a dictionary, I could have looked the word up.
- He didn't prepare for the interview, so he didn't get the job.

=> If he had got the job, he would have prepared for the interview.

#NOCOPY

I don't know you are coming, so I don't invite some friends in

⇒if i had known you are coming,i would have invited some friends in

I can't look the word up because I haven't got a dictionary

⇒if i had got a dictionary,i could have looked the word up

He didn't prepare for the interview, so he didn't get the job

⇒if he had prepared for the interview,he would have got the job

cấu trúc câu đk loại 3:

if+S+had+pp²,S+would/could/might+have+pp²