问题 选择题

如图所示是阴极射线示波管的聚焦电场。实线为电场线,虚线为等差等势线。a、b、c为从左侧进入聚焦电场的电子运动的轨迹上的三点。不计电子的重力,则

A.电场中a点的电势高于c点的电势

B.电子经a点的动能大于经c点的动能

C.电子经b点的加速度大于经c点的加速度

D.电子经b点的电势能大于经c点的电势能

答案

CD

题目分析:沿电场线方向电势降低,故a点的电势低于c点的电势,A错误;电子由a点运动到c点的过程中,电场力做正功,电势能减小,动能增大,故B错误D正确;等差等势面密集处电场强度大,故电子受到的电场力大,加速度大,故C正确。

阅读理解

阅读理解。

     Monday of this week is Christmas'Day. Did you get some presents on this Christmas Day?

     A Christmas Day is the most important festival in Britain and some other countries. On Christmas Eve

(December 24th), people usually tell their children to put their stockings* at the end of their beds before

they go to sleep.

     Children believe Father Christmas will bring them Christmas presents. Actually, Father Christmas is

children’s father. He dresses up in a red coat and waits until children fall asleep. Then he goes into

children’s bedrooms, and puts small presents in their stockings. When childrenre no longer young, they

know who Father Christmas really is.

     Not only children but also their parents enjoy Christmas stockings. They also have stockings. Early

on the morning of Christmas Day, children wake their parents up say “Merry* Christmas”. Then they

help their parents open their stockings. Everybody likes presents. But it is better to give than to receive.

In France, everyone has a Christmas tree, sometimes decorated in the old way with red ribbons* and

white candles*. Trees in the garden are often decorated too, with lights on all night. Father Christmas is

called Pere Noel in France. The Christmas meal is an important chance for family to get together with

good meat and the best wine. Not everyone sends Christmas cards.

     In Germany, people love to decorate their houses with some beautiful small things at Christmas.

Father Christmas brings presents in the late afternoon of Christmas Eve, after people have been to a

church meeting. The presents are then found under the Christmas tree. One person in the family will

ring a bell and call everyone to come to the room. On Christmas Day, some delicious food will be

cooked.

1. What do all the British children do on Christmas Eve in the story?

A. They talk all the night.

B. They sing and dance.

C. They put their stockings at the end of their beds.

D. They won’t sleep until Father Christmas comes.

2. What’s the meaning of "decorate" in the article?

A. 买

B. 装饰

C. 刷新

D. 点亮

3. Who is real Father Christmas according to this article?

A. Pere Noel.

B. Children’s father.

C. Children.

D. Children’s mother.

选择题