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

3 . 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

5 . The beautiful and charming song has been heard________many times today.

A．to broadcast

B．being broadcast

C．broadcasting

D．broadcast

6 . 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）

7 . —How long do you think it will be ________ China sends a manned spaceship to the moon?
—Perhaps two or three years.

A．when

B．before

C．that

D．until

8 . 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).

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