外圆磨床液压系统因为采用了()换向回路,从而使工作台运动获得了良好的换向性能,提高了

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问题:

外圆磨床液压系统因为采用了()换向回路,从而使工作台运动获得了良好的换向性能,提高了换向精度。

A、压力控制制动

B、时间控制制动

C、行程控制制动

D、电气控制制动

考点:煤炭矿山职业技能鉴定考试煤矿机械安装工(综合练习)煤矿机械安装工(综合练习)题库
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阅读理解。

    It was half-past eight in the morning. The telephone bell rang and Mary went to answer it. It's me-Peter.

Hello, who's that? she asked.

    Peter was a friend of Mary's eight-year-old brother, Johnny.

    Oh hello, Peter. What do you want? said Mary.

    Can I speak to Johnny?

     No, said Mary, you can't speak to him now. He is busy. He is getting ready for school. He is eating his

breakfast. Grandmother is combing his hair. Sister is under the table, putting his shoes on. Mother is getting

his books and putting them in his school bag. Goodbye, I've got to go now. I have to hold the door open.

The school bus is coming.

1.Who went to answer it when the teltphone bell rang? [ ]

A.Johnny's sister

B.Peter

C.Johnny

D.Johnny's mother

2.Whom did Peter want to speak to? [ ]

A.Mary's brother

B.Mary's sister

C.Mary's grandmother

D.Johnny's mother

3.Johnny couldn't speak to Peter because Johnny ______. [ ]

A.was combing his hair

B.was putting his shoes on

C.was getting his books

D.was busy eating his hreakfast

4.How do you say to a stranger who is answering your telephone?[ ]

A.Who are you?

B.Anything to say?

C.Who is it?

D.Please

5.From this story we know that Johnny was _____. [ ]

A.a lazy boy

B.a clever boy

C.a busy boy

D.a hungry boy

题型:单项选择题

. ______ they obtain from the activities is very important to the training in their character.

A.That

B.Which

C.What

D.How

题型:单项选择题

水仓、沉淀池和水沟中的淤泥,应及时清理,每年()前必须清理一次。

A.春季

B.雨季

C.秋季

D.冬季

题型:单项选择题

一般万用表上有两个切换开关,一个用来改变测量种类;另一个用来改变量程。

题型:单项选择题

判定某可比实例的成交价格比正常价格低6%,则交易情况修正系数为( )。

A.0.060

B.0.940

C.1.060

D.1.064

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