1. Complete the sentences with the following phrases.(词组填空)

catch on      on purpose       provided that       be aware of    differ from   consist of     get ahead       congratulate…on    focus on    sign up   in the absence of     hold the key to

1. （1） I don't to what he is saying.
3. （2） She broke the dish just to show her anger.
5. （3） I don't mind Mary coming with us he pays his own meals.
7. （4） Most smokers perfectly the dangers of smoking.
9. （5） Humans other mammals in their ability to speak.
11. （6） Class 13 4 lovely girls and 55 hard-working boys.
13. （7） She soon found that it wasn't easy to in the movie business.
15. （8） any evidence, the police had him go.
17. （9） The weather our success or failure.
19. （10） We our team coming first in the competition.