甲、乙两物体的质量之比为m甲:m乙=1:4,若它们在运动过程中的动能

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问题选择题

甲、乙两物体的质量之比为m_甲:m_乙=1:4,若它们在运动过程中的动能相等,则它们动量大小之比p_甲:p_乙是（）

A．1:1

B．1:2

C．1:4

D．2:1

答案

答案：B

句型转换

句型转换。

1. My parents should allow me to study with friends.(改为同义句)

I should ______ ______ to study with friends.

2. They oft en clean their classroom after school. (改为被动语态)

Their classroom ______ often ______ by them after school.

3. Li Lei gave Tom a new pen last week. (改为被动语态)

A new pen ______ ______ ______Tom last week.

4. It took him ten years to finish writing the book. (改为同义句)

He ______ ten years ______ the book.

5. They will publish these story-books next month. (改为被动语态)

These story-books ______ ______ ______ next month.

单项选择题

某地2001年平均人口数为100 000，该地防疫站收到2001年发病的菌痢传染病报告卡323张，剔除重复，实际报告的菌痢患者为260人，在此260人中有 3人发病2次，则该地菌痢的报告发病率为

A．323/10万
B．260/10万
C．326/10万
D．263/10万
E．257/10万