Past perfect or simple past

In the following sentences, use past perfect or simple past tense of the verbs given in parentheses. Read each sentence carefully before you choose the verb; remember that if the time word before or after makes the time relationship clear, you do not have to use past perfect. 

Example: Class already (start) by the time I arrived. Class already had started by the time I arrived.



 1. Molly (be) a teacher before she (become) a lawyer.
 2. Yesterday I (see) Susan Chan, an old friend whom I (see, not) in many years. At first, I (recognize, not) her because she (gain) fifty pounds.
 3. Joe suddenly (realize) that the teacher (ask) him a question.
 4. It (be) midnight when I finally (go) to bed. 
5. I (feel) better after I (take) some medicine. 
6. When I (go) to see my math teacher about why I (receive) a failing grade on the last test, he (examine) my paper and then (announce) that he(make) a mistake and (change) my grade to an "A." 7. When I (try) to explain to my friend why I (call, not) him in several weeks, he (tell) me not to worry because he (be) out of town for a month. 
8. When Sharon and Will (get married) last month, they (knew) each other for only two weeks.
 9. I (go) to the movies after I (finish) my homework even though I (see) the movie many times.
 10. Jerry (come) to the party, but no one (invite) him