题干

在厚钢板上加工如图所示的孔径,上半部分为螺纹外径M6的螺纹孔,下半部分为Φ12的光滑圆孔,以下加工方法不合理的是(   )

A:用样冲冲眼,防止钻孔滑移

B:用Φ6的麻花钻钻出通孔

C:用Φ12的钻头钻出下半部分的光滑圆孔

D:用M6的丝锥加工出上半部分的螺纹

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答案(点此获取答案解析)

B

同类题1

从A-F中选择其中五个填入短文中相应空格处,其中一个选项是多余。

Giving directions in different places

    If you ask people of different countries "Could you tell me the way to the post office?", you will get different answers.

    In Japan, people use landmarks instead of street names. For example, the Japanese will say to travelers, "Go straight down to the corner. ____ The post office is across from the bus stop."

    In Kansas, America, there are no towns or buildings within miles. So instead of landmarks, people will tell you directions and distance. For example, people will say, "Go north two miles ____".

    People in Greece sometimes do not even try to give directions. They will often say, "Follow me." ____ Sometimes if a person doesn't know the answer to your question, he or she, like a New Yorker, might say, "Sorry, I have no idea." But in Yucatan, Mexico, no one answers "I don't know". ____ They usually give an answer, but often a wrong one. A visitor can often get lost in Yucatan!

____ You might not understand a person's words, but maybe you can understand his or her body language. He or she will usually point to the correct direction. Go on in that direction and you may find the post office!

A. Turn east, and then go another mile.

B. But one thing will help you everywhere.

C. People there think "I don't know." is not polite.

D. Turn left at a big hotel and go past a fruit market.

E. Then he or she will take you through the streets of the city to the post office.

F. Sorry, I don't know, I'm a stranger here.