1) I haven't finished my homework yet.
2) I have already done my homework
3) I have just finished my homework
4)He has already gone home
5) Mark has just come back from France
6) They have just bought a new house
7) We haven't had lunch yet.
8) The train has already left the station
9) Has the train left yet?
Объяснение:
(n)ever, just, already ставятся между have и глаголом в третьей форме
yet - всегда в конце предложения.