Answered

1. We.......each other since we were in the kindergarten.
a. Know b. are known c. have known
2. .....your parents already............ their tickets for the concert?
A. Did\buy b. Have\bought
c. Are\buying
3. They haven't prepared well for their family gathering...........
A. Already b. for c. yet
4. There haven't been any delays so we will be there......time
a. At b. on c.by
5. I am feeling tired. I don't think. ..................tonight.
a. Go out b. 'll go out
6. If I were in
A. May
c. 'm going out
Susie's position. I ....... leave and get another job.
b. might c. must