They haven't done it yet.
O
They have not just done it.
They has not done it already.
0 My sister hasn't gone to Canada.
O My sister haven't gone to Canada.
U My sister hasn't gone in Canada.​

1) I have been to St Petersburg. I was in St Petersburg in 2003. 2) He has been to South America. He was in South America last month. 3) They have been  to France They were in France three years ago 4)  He has had lunch. He had lunch twenty minutes ago. 5) We  have done the exercises . We did the exercises an hour ago . 6)  He has cooked dinner. He cooked dinner ten minutes ago. 7) I have read the book. I read the book when I was seven. 8) She has left Moscow.  She left Moscow last week 9. We have telephoned him. We telephoned him yesterday  10) They have found  the key.  They found the key ten minutes ago.

1.   If I were you, I would learn how to drive a car. (learn)
2. if I only I knew where he works. (know)
3.   If we had called the travel agent earlier, we would have gotten tickets to Toronto.(get)
4.   If Matthew arrived earlier to the party, he would see
Billy.(arrive)
5I wish I didn't have the flu. (have not)
6.What would you do if your car broke in the middle of nowhere? (break)
7. If the service in a restaurant is bad, you are not expected to leave a tip.
8. If you plan to visit someone at home,  you are  supposed to call first.
9.  If  I am invited to the party, I  will buy a nice present.
10.   I wish I didn't faint when there is an emergency.(not/ faint)