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问题 问答题 简答题

识别断层的地貌标志。

答案

参考答案：

断层活动及其存在，常常在地貌上有明显表现，它为观察和确定断层提供了重要线索。

（1）断层崖；

（2）断层三角面；

（3）错断的山脊；

（4）山岭和平原的突变；

（5）串珠状湖泊洼地；

（6）带状分布的泉水和地震震中；

（7）水系特点。

填空题

二氧化碳的实验室制法

（1）原理：用石灰石和稀盐酸反应：______（写出反应的化学方程式）

（2）选用和制氢气相同的发生装置．

（3）气体收集方法：应用向______排空气法，______用排水法

（4）验证方法：______，则是二氧化碳．

验满方法：______，证明已集满二氧化碳气体．
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单项选择题

The United States has historically had higher rates of marriage than those of other industrialized countries. The current annual marriage (51) in the United States—about 9 new marriages for every 1,000 people—is (52) higher than it is in other industrialized countries. However, marriage is (53) as widespread as it was several decades ago. (54) of American adults who are married (55) from 72 percent in 1970 to 60 percent in 2002. This does not mean that large numbers of people will remain unmarried (56) their lives. Throughout the 20th century, about 90 percent of Americans married at some (57) in their lives. Experts (58) that about the same proportion of today’s young adults will eventually marry.

The timing of marriage has varied (59) over the past century. In 1995 the average age of women in the United States at the time of their first marriage was 25. The average age of men was about 27. Men and women in the United States marry for the first time at an average of five years later than people did in the 1950s. (60) , young adults of the 1950s married younger than did any previous generation in U. S. history.

58().

A.project 

B.plan 

C.promise 

D.propose
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