Are используется когда с местоимениями you,we,they,а is-с местоимениями he,she ,it.Например:She IS a girl.We ARE students.
1) d; has repaired
2) a; have left
3) b; has just returned
4) e; have been
5) f; haven't finished
6) c; have bought
9 came
10 was told
11 was allowed
12 was
13 sat
14 waiting
15 placed
16 passed
17 didn't appear