1 . 从下列所给词组中选用正确的词组并以适当的形式填到句子中，每个词组仅能用一次。

give way                           crack a smile                    pay off                                 (be) worthy of      in turn                                 take off                           cross out                                 due to              concentrate on                    turn down                    make sense                           pick up

1. The environmental challenges are significant, but the efforts made by the Tanzania National Park Authority seem to be ________.
2. Most people find the start of the week so exhausting that we can't even ________ until 11 a.m.
3. She can't remember how many times she ________ before getting her first job as a salesgirl.
4. ________ my homework, I didn't notice they had sat down behind me.
5. About 20 years ago, the practice of hunting tourism ________ because of the interest from photographic lovers.
6. Some Internet buzzwords can only ________ with the context of Internet.
7. The dogs serve to protect humans against pumas, which ________ prevents pumas from being hunted by humans.
8. Your composition will read better if you ________ these words and replace them with fine figures of speech.
9. ________ circumstances beyond our control, the flight to Rome has been cancelled.
10. She was going over to her parents' house ________ some clean clothes for Oskar.