PAST PERFECT vs PAST SIMPLE

I  (study) Japanese before.

She  (bake) a lot before she  (open) her shop.

We  (have) a lot of trouble because we  (lose) our passports.

Brian  (know) many people at the club because he  (be) there many times.

They  (study) English before they  (move) to Canada.

She  (enjoy) the movie because she  (read) the book.

Amy  (study) a lot before she  (take) the test.

Chris  (own) that car for 5 years before he  (sell) it.

They  (have) a lot of trouble before they finally  (succeed).

  I (open)  the door and (see)  a police officer standing there.

I  (be) in Greece for 7 months before I  (move) to Spain.

A plumber (come)  to our house yesterday.