1 . We all need to get involved in saving energy ________ it's at work, at home, or at school.

A．unless

B．once

C．whether

D．because

2 . Henry David Thoreau was happy to ________ from social life, seeking a harmonious relationship with nature in the quietness of his life.

A．judge

B．differ

C．withdraw

D．benefit

4 . Canada will___________smoking in all offices later this year. (根据句意填空)

5 . Of the nineteen recognized polar bear subpopulations, three are declining, six ________ (be) stable, one is increasing, and nine lack enough data.(所给词的适当形式填空）

6 . The Xi’an City Wall is the most complete city wall that has survived China’s long history. It ________ (build) originally to protect the city in the Tang Dynasty and has now been completely restored (修复).

7 . My bike was old and shaky ________ did the job.（用适当的词填空）

8 . It was the first time in six attempts that Peters ______the world champion.

A．has beaten	B．was beaten
C．beat	D．had beaten

9 . The ________ (beauty) long branches covered with pink-colored buds (蓓蕾) make fantastic decorations. （所给词的适当形式填空）