20世纪70年代以后，发达国家人口自然变动的特征是（）A.高出生率

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问题单项选择题

20世纪70年代以后，发达国家人口自然变动的特征是（）

A.高出生率、高死亡率、低自然增长率

B.低出生率、低死亡率、低自然增长率

C.高出生率、低死亡率、高自然增长率

答案

参考答案：B

填空题

根据所给的汉语注释，在横线上写出各单词的正确形式

1. Iron_______ ( 钉子)will rust if put in ordinary water.

2. Our school has just been equipped with a big electronic _______( 银屏).

3. Every day he takes half an hour's ride to school because he lives in the_______(郊区).

4. The brilliant expert gave us a wonderful_________( 演讲 )last Friday.

5. Our headmaster will make a speech at the opening________(仪式) of the school sports meet.

6. Quite a few families in the city now can _________( 承担 ) a private car.

7. In the past, some people traveled to_________( 幸存 ).

8. With the society progressing, nobody in my village is ________( 挨饿 ) now.

9. The stars shone in the sky just like _________( 钻石 ) on that summer night.

10. Our English teacher is an_________( 热情 ) and friendly middle-aged man.

填空题

在△ABC中，∠C=90°，a=9，c=15，则sinB=______，b=______．