问题 选择题

已知直线l与直线m是异面直线,直线l在平面α内,在过直线m所作的所有平面中,下列结论正确的是(  )

A.一定存在与l平行的平面,也一定存在与α平行的平面

B.一定存在与l平行的平面,也一定存在与α垂直的平面

C.一定存在与l垂直的平面,也一定存在与α平行的平面

D.一定存在与l垂直的平面,也一定存在与α垂直的平面

答案

A:根据空间中线面的位置关系可得:当性质m与平面α斜交时,不存在与α平行的平面.所以A错误.

B:根据空间中线面的位置关系可得:一定存在与l平行的平面,也一定存在与α垂直的平面.所以B正确.

C:由空间中线线的位置关系可得:当直线l与m不垂直时,不存在与l垂直的平面.所以C错误.

D:由空间中线线的位置关系可得:当直线l与m不垂直时,不存在与l垂直的平面.所以D错误.

故选B.

阅读理解

阅读理解。

     When I was a boy, I liked swimming very much. One year my two brothers and I spent the summer

holidays with my uncle and aunt in their house by the sea. It was only twenty meters from the water.

Every day we put on our swimming shorts before breakfast, ran down to the sea and jumped in. From

then until late in the afternoon we were in the sea of the time. When our aunt rang the bell, we went back

to the house for food, but we ate it in our swimming shorts and were soon back in the sea again. The

water was warm, the sun shone every day and on most days there were no waves. In the middle of the

day a wind always began to blow, but it was not strong.    

     Three times during our holidays we had strong winds. They made big waves in the sea. But we were

all good swimmers and didn't stop swimming until we were tired and happy.

1. The boy _____. [ ]

A. had two brothers

B. lived by the sea with his parents

C. learned to swim a few months ago

D. went to his uncle's house every day

2. One year the boy _____.[ ]

A. went out to look for food by himself

B. learned to swim from his uncle and aunt

C. ran down to the sea every morning

D. went to spend the summer holidays in his uncle's house

3. The boy's uncle and aunt _____. [ ]

A. liked swimming very much

B. the wind always started to blow

C. often took the children down by the sea

D. rang the bell when it was time for breakfast

4. In the middle of the day _____. [ ]

A. there were no waves in the sea

B. the wind always started to blow

C. the sun came out from the cloud

D. the wind began to grow strong

5. The boy and his brothers _____. [ ]

A. swam three times a day

B. did not take a rest until their aunt rang the bell

C. had strong winds three times during their stay at their uncle's

D. did not go swimming when the wing was strong

单项选择题