6.When we went to Japan,my friend_____________a lot about the city because she___________there many times.

A.was,had known
B.knew,had been
C.had known,was
D.had been,knew

7.It was a very difficult movie,but i _________it because i__________the book.

A.had understood,read
B.have not read,understood
C.read,has understood
D.understood,had read​