质量为m的木块，在平行斜面向上的拉力F作用下，沿倾角θ的粗糙斜

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问题选择题

质量为m的木块，在平行斜面向上的拉力F作用下，沿倾角θ的粗糙斜面上滑行L距离。物体所受各力做功为零的是 [ ]

A．重力G

B．支持力N

C．摩擦力f

D．拉力F

答案

答案：B

选择题

Don't forget to _____ the lights when you leave the classroom. [ ]

A. turn on

B. turn off

C. turn up

D. turn down

听力题

根据句意, 用括号中所给词的适当形式填空。

小题1:Will people live 100 years old? ( be )

小题2:Mother (sweep) the floor when I (leave) home.

小题3:My friend Eve told me she (be) going to buy a new computer.

小题4:It’s necessary for young people (experience) different things.

小题5:My dream is to be a (profession) athlete.