1 . The team ______ (start) a campaign to save endangered species before the media answered the call. （所给词的适当形式填空）

2 . By the time I ______ (finish) my homework, my family ______ (cook) dinner already.（所给词的适当形式填空）

3 . They ______ (live) in China for two years before they ______ (decide) to move to Canada. （所给词的适当形式填空）

4 . Life went on________ (primitive) until the day when the telephone was brought into the village.（所给词的适当形式填空）

5 . Train fares (费用) are likely to remain ________ (change). （所给词的适当形式填空）

6 . A botanist can differentiate________ (vary) of plants. （所给词的适当形式填空）

7 . The first mention of the________ (discover) appeared in an article last year.（所给词的适当形式填空）

8 . The students of the ________ (geology) class will be out on field exploration（所给词的适当形式填空）

9 . Police said there were no ________ (suspect) circumstances about the boy’s death. （所给词的适当形式填空）

10 . He was disgusted that a British minister could have behaved so ________ (disgrace). （所给词的适当形式填空）