阅读短文，然后从方框中选出可以填入文中空白处的单词
teacher but old learn with boring basketball history musician
Mr. and Mrs. Cooper are Americans. But now they are in Beijing ____ their kids. This is their first time to China.
Mr. Cooper is a ____. He sings very well. Mrs. Cooper is a ____. Her daughter studies at her school. Mrs. Cooper likes Beijing Opera very much. She thinks she can learn about Chinese ____ and culture. So she often goes to see Beijing opera. ____ her daughter doesn’t think so. She likes comedy , and her favorite movie is Mr. Bean. Mr. Cooper doesn’t like movies. He thinks they are____. He likes sports. His favorite sport is ____ . He likes Yao Ming very much.
The Coopers want to go to Pingyao, Shanxi. It is an ____ and nice place. They want to take photos there. They can also____to speak Chinese. They can have a good time in China.
和
的圆环，两圆环上的电荷量均为q（q>0），而且电荷均匀分布。两圆环的圆心
和
相距为2a，联线的中点为O，轴线上的A点在O点右侧与O点相距为r（r<a）。是分析判断下列关于A点处电场强度大小E的表达式（式中k为静电力常量）正确的是
