将一个物体以某一速度从地面竖直向上抛出，设物体在运动过程中所

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问题不定项选择

将一个物体以某一速度从地面竖直向上抛出，设物体在运动过程中所受空气阻力大小不变，则物体[ ]

A．刚抛出时的速度最大

B．在最高点的加速度为零

C．上升时间大于下落时间

D．上升时的加速度等于下落时的加速度

答案

答案：A

句型转换

句型转换。

1. He has to make dinner at home. (改为否定句)

He ____ ____ to make dinner at home.

2. He has to do his homework after school. (对划线部分提问)

____ does he have to ____ after school?

3. Come to the party at 5 o'clock, please. (改为否定句)

____ ____ to the party at 5 o'clock, please,

4. What else do you have to do? (改为同义句)

What ____ ____ do you have to do?

5. They can play tennis in the gym. (改为一般疑问句)

____ they ____ tennis in the gym?

问答题简答题

简述何谓继发性 * * Paget病。