问题
单项选择题
地壳的平均厚度是（）
A.7千米
B.17千米
C.33千米
D.35千米
答案
参考答案：B
解析：
科学家经过长期的精密测量，发现地球是一个两极稍扁、赤道略鼓的不规则球体。大陆地壳平均33千米，海洋地壳平均6千米，地壳的平均厚度约17千米，故选B。
考点：地球的大小。
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地壳的平均厚度是（）
A.7千米
B.17千米
C.33千米
D.35千米
参考答案：B
解析：
科学家经过长期的精密测量，发现地球是一个两极稍扁、赤道略鼓的不规则球体。大陆地壳平均33千米，海洋地壳平均6千米，地壳的平均厚度约17千米，故选B。
考点：地球的大小。
完形填空。 |
| Mrs. Brown has a small 1 in front of her house. In spring she plants some 2 in it." She looks 3 them very carefully. When summer comes, they look very nice. One evening Mrs. Brown looked at her vegetables and said "Tomorrow I am going to pick 4 , and then we can eat them." But early the next morning, her son 5 into the kitchen and shouted, "Mother, Mother! Come quickly! Our neighbor's ducks 6 in the garden. They are eating our vegetables!" Mrs. Brown ran 7 but it was too 8 ! All the vegetables were eaten up! Mrs. Brown cried and her neighbor was very 9 , but that was the end of the vegetables. Then a few days before Christmas, the neighbor brought Mrs. Brown a parcel (包裹). There was a beautiful fat duck in it, and it was a piece of paper 10 the words "Enjoy your vegetables!" |
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