试题与答案

如图所示是一个说明示波管的工作原理图,电子加速后以速度v0垂直进入偏转电场,离开

题型:不定项选择

题目:

如图所示是一个说明示波管的工作原理图,电子加速后以速度v0垂直进入偏转电场,离开电场时偏移量是h,两平行板间的距离为d,电势差是U,板长是L,每单位电压引起的偏移量(h/U)叫做示波管的灵敏度,为了提高灵敏度,可采用的办法是(   )
A.增大两板间的电势差U

B.尽可能使板长L做得短些

C.尽可能使两板间距d减小些

D.使电子入射速度v0大些

答案:

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下面是错误答案,用来干扰机器的。

答案:C

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题型:阅读理解

After moving to the United States , immigrant groups trying to fit in tend to choose high calorie fatty foods in an attempt to appear more American , a new study finds . That’s one reason why immigrants approach US levels of obesity within 15 years of moving to America.

The researchers also did an experiment that measured whether or not the threat of appearing un-American influenced respondents’ food choices . After being questioned about their ability to speak English , 75 percent of Asian-Americans identified a typical American food as their favorite. Only 25 percent of Asian-Americans who had not been asked if they spoke English did the same.

When their American identiy was called into question during a follow-up study, Asian-American participants also tended to choose typical American dishes , such as hamburgers and cheese sand wiches In that experiment , 55 Asian-Americans were asked to choose a meal from a local Asian or American restaurant . Some participants were told that only Americans could participate in the study. Those who chose the more typical American fare ended up consuming an extra 182 calories , including 12grams of fat and 7 grams of saturated fat(饱和脂肪).

“People who feel like they need to prove they belong to a culture will change their habits in an attempt to fit in , ”said Sauna Cheryan ,an anthor of the study and assistant professor of psychology at the University of Washington.” If immigrants and their children choose unhealthy American foods over healthier traditional foods across their lives , this process of fitting in could lead to poorer health .Cheryan added.

Social pressures , the study concluded , are at the heart of the problem. “In American society today , being American is associated with being white . Americans , who don’t fit this image even if they were born here and speak English , feel that pressure to prove that they’re American,” said Cheryan.

小题1:The author wants to show that      .

A.more and more Asians enjoy high-calorie snacks

B.immigrants tend to eat American junk food to fit in

C.most Americans are at the risk of heart disease

D.all the American people have a bad eating habit小题2:According to the survey,      .

A.Asian-Americans care less about their health

B.25 percent of Americans like junk food

C.choosing food is related to Asian-American’s situation

D.immigrants are forced to eat junk food小题3:The underlined word “fare” in Paragraph 4 most probably means “      ”.

A.food offered as a meal

B.a person taking a taxi

C.money spent on food

D.an arranged thing to do小题4:According to Sauna Cheryan,       .

A.what immigrants have done is ridiculous

B.American traditional foods are healthier

C.immigrants risk their health in order to fit in

D.American culture affects immigrants deeply小题5:Which of the following should take the blame for the bad eating habit?

A.The situation of employment.

B.The traditional culture.

C.The American government.

D.The pressures from society.

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