词汇运用。

1. You should remember that __________ (微笑) always helps.

2. He lives ___________ (孤单地) in a small town, but he never feels lonely.

3. The music ___________(听起来)so wonderful.

4. She has __________ (从未) wanted to visit the USA.

5. Would you please show me __________ (另外的) one? I don't like this camera.

6. I have been to America _________ (两次).

7. He gave me a few pieces of ___________(建议)on learning English.

8. He ________ (退学) out of school because his family was poor.

9. Tom's father has been  ___________ (出国) many times.

10. Mozart was a great _______  (音乐家) in Austria.

实验室提供下列盛有药品的仪器，让两个实验小组各自证明某一混合气体中含有二氧化碳. 一氧化碳和水蒸气。

用A. B. C. D填空

（1）甲组分别证明混合气体中含有某一种气体：

① 证明其中含有CO₂，选用                  ；

② 证明其中含有水蒸气，选用                  ；

③ 选择必要的仪器（每种只用一次）证明其中含有CO，按气体通过的先后顺序依次是                 。

（2）乙组用上述仪器（每种只用一次）组装一套装置，通过一次实验证明混合气体中含有二氧化碳. 一氧化碳和水蒸气，则应该将                中的药品换成Ba(OH)₂溶液，按气体通过的先后顺序，连接的仪器依次是                       。