He felt it strange ______ she would be late for class.
A. that
B. which
C. when
D. why
Don't forget to turn off the heating before ______ the house.
A. 1cave
B. left
C. to lcave
D. leaving
When he ______, tell him that I've already left.
A. has come
B. came
C. comes
D. will come
______ a contract last year and it is still valid.
A. We have signed
B. We signed
C. We haven't signed
D. We have signed