搜题请搜索小程序“爱下问搜题”
问题 不定项选择

如图甲所示，变压器原副线圈匝数比为22：1，原线圈与正弦交变电源相连，副线圈与电阻R、交流电压表按图示方式连接，R＝10Ω，交流电压表的示数是10V，图乙是电阻R两端电压uR随时间t变化的图像，则

[ ]

A．R两端的电压uR随时间t变化的规律是

B．图乙中U0=10V

C．变压器原线圈中电流i随时间t变化的规律是

D．交变电源的电压u随时间t变化的规律是

答案

答案：D

听力题

根据下列短文内容，在短文的空格处填上一个恰当的词，是短文完整、通顺。

What are you going to do if you are in a burning house? How will you escape? Do you know how to  小题1:  yourself? Please read the following passage.

Escaping a fire is a serious matter. Knowing  小题2:   to do during a fire can save your life. It is important to know the   小题3:   you can use and show them to everyone in the family, such as stairways and fire escapes, but not lifts.

From the lower floors of the buildings, escaping   小题4:   windows is possible, the second floor window is usually not very high from the ground. Though it’s a little dangerous, it is  小题5:  to jump a short way than to stay in a burning building.

Windows are also useful when you are    小题6:   for help. Be sure to keep the door   小题7:  . Or smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get fresh air rather than  小题8:   that may leaked into the room.

On a second or third floor, the best windows for escape are those that open onto a roof . From the roof of a person can drop to the ground more easily.
查看答案
单项选择题

RIP的作用有（）。

A、解释JPEG文件

B、生成图形

C、生成图像

D、控制输出
查看答案