问题 选择题

如图所示,光滑的水平桌面处在竖直向下的匀强磁场中,桌面上平放着一只内壁光滑的玻璃试管,管的底部M处有一带电小球。在水平拉力F作用下,试管向右做匀速运动时,小球向管口N运动,则 

A.小球带负电

B.小球带正电

C.在小球未从管口出去前,小球做匀速运动

D.在小球未从管口出去前,拉力F不断增大

答案

BD

根据小球的运动把它分解成两个互相垂直的分运动,向右匀速使小球向管口N运动,说明小球受到沿管口方向的恒力,根据左手定则小球带正电。B对;向管口做匀加速直线,是小球受到向左的洛仑兹力,向右匀速所以小球受到的拉力必须越来越大。D对。

完形填空

How time flies, our junior high school (初中) years are coming to an end. After the big exam,most of us will go to          in a senior high school (高中).        are we expecting from senior high? We interview some tudents about their plans for future. Now          hear what plans some students have for the future.

Jerry, 16, from Shanghai, “I have heard that although Senior 3 is a         year, students feel less stressed out in Senior 1 and Senior 2. I hope there’ll be time to enjoy       , especially tennis. The Tennis Masters (大师) Cup will be held in Shanghai. I’m going to volunteer to help out and I’m sure I’ll really enjoy it.”

Han Lily, 15, from Zhongshan, “I really enjoy science. I’m crazy about          model planes, although I’m not good at         . I’ll learn more science in senior high. Anyway, sometimes in the future I’m going to build a super model plane!”

Wan Yang, 17, from Xiamen, “I hope I can be         in senior high school. I’m only 155 cm. I want to be 162 cm.        most of the girls in my family don’t grow any taller than 160 cm. I hope I’m different.”

Li Fan, 16, from Shenzhen, “I hope I can make more friends. In senior high, I’ll meet different people from different areas. I hope I can learn new things         them.”

小题1:

A.walk

B.study

C.play

D.write小题2:

A.When

B.How

C.What

D.Where小题3:

A.let’s

B.it’s

C.what’s

D.that’s小题4:

A.hot

B.hard

C.light

D.kind小题5:

A.book

B.show

C.photo

D.sports小题6:

A.making

B.sitting

C.cooking

D.cleaning小题7:

A.us

B.him

C.it

D.her小题8:

A.shorter

B.stronger

C.thinner

D.taller小题9:

A.So

B.But

C.When

D.If小题10:

A.to

B.for

C.from

D.at

填空题