问题 选择题

下列说法正确的是(  )

①平分弦所对两条弧的直线,必经过圆心且垂直平分弦.

②圆的切线垂直于圆的半径.

③在同圆中,相等的弦所对的圆周角相等.

④在同圆中,弦心距越大则该弦越短.

A.1个

B.2个

C.3个

D.4个

答案

因为平分弦所对的两条弧的直线,必经过圆心,且垂直平分弦,所以第一个论述是正确的,∴①正确;

∵圆的切线垂直于过切点的半径,∴②错误;

∵在圆中,任何一条弦都对应着两条弧,而这两条弧一般是不相等的,只有弦是直径时,所对的两条弧才相等,∴③错误;

∵由垂径定理和勾股定理

得出BE<CF,

即AB<CD,∴④正确;

∴正确的有2个,

故选B.

阅读理解

Living in a foreign culture can be exciting, but it can also be confusing(令人迷惑的). Some Americans who taught English in other countries recently talked about their experiences.

On her first day in Micronesia(密克罗尼西亚), an island in the Pacific, Lisa thought people weren’t paying any attention to her. It was hot. She went into a store and asked, “Do you have cold drinks? ” The woman there said nothing. Lisa repeated the question. Still the woman said nothing. She later learned that the woman had answered her: She had raised her eyebrows(眉毛), which in Micronesia means “yes”.

Jane remembered an experience she had in Bulgaria(保加利亚), a country in Europe. She went to a restaurant. She asked the waiter, “Do you have cabbage today?” He nodded his head. Jane waited, but the cabbage never came. In that country, a nod means “no”.

Tom had a similar problem when he arrived in India. After explaining something in class, he asked his students if they understood. Some nod and others shake. He thought some students had not understood, so he explained again. When he asked again, they did the same thing. He soon knew that his students did understand. In India, people nod and shake their heads in different ways depending on where they come from. You have to know where a person is from to understand whether they mean “yes” or “no”.

小题1:These Americans in the passage found that they__________ .

A.should go abroad for vacations

B.needed to learn foreign languages

C.should often discuss their experiences

D.had problems with communication in other countries小题2:People in Micronesia show “yes” by ________ .

A.nodding heads

B.raising eyebrows

C.shaking heads

D.saying “no”小题3:Tom misunderstood(误解)his class at first because_______ .

A.he didn’t know much about Indian culture

B.he didn’t explain everything clearly enough

C.some students didn’t speak English

D.he didn’t know where the students came from小题4:Which of the following is TRUE?

A.In Bulgaria, nodding heads means “no”.

B.Jane taught English on a Pacific island.

C.Lisa was trying to buy some cabbage.

D.In India, only shaking heads means “yes”.小题5:The passage is mainly about_________ .

A.body language in foreign restaurants

B.class discussion in Indian schools

C.different language cultures in different countries

D.English teaching in other countries

填空题