声是由物体的振动产生的．风吹树叶哗哗响，是 ______在振动．笛

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问题填空题

声是由物体的振动产生的．风吹树叶哗哗响，是 ______在振动．笛子等管乐器发出动听的声音，是由 ______振动产生的．

答案

风吹树叶哗哗响，这是由树叶的振动发出的声音；

笛子是管乐器，声音是由空气柱的振动发出的．

故答案为：树叶；空气柱．

填空题

单词拼写：根据下列句子及所级汉语注释，写出空缺处各单词的正确形式。（每空只写一词）

1. The course will start in ______ (十二月).

2. She ______ (提醒) me that I hadn't written to Mother.

3. I hope to be back in a ______ (两星期).

4. My ______ (最喜欢的) colour is green.

5. The baby in the next room ______ (睡醒) and began to cry.

6. ______ (水桶) are often used for holding and carrying water.

7. They look like the teeth of a ______ (凶猛的) animal.

8. It is ______ (危险的) for children under five years old to be left alone at home.

9. Because of this special experience, he was chosen to be an ______ (助理) to the president for

energy affairs.

10. Two years later, he left his parents and entered a ______ (医学的) college.

单项选择题 A1/A2型题

下列何种细胞分泌盐酸（）

A.黏液颈细胞

B.主细胞

C.壁细胞

D.黏液细胞

E.G细胞