东风4C型内燃机车大修规程规定机油管路检修时,管路开焊允许焊修,焊后需经磷化处理,并

题型:填空题

问题:

东风4C型内燃机车大修规程规定机油管路检修时,管路开焊允许焊修,焊后需经磷化处理,并作0.8Mpa油压试验,保持5min,()

考点:机车车辆管道工机车车辆管道工(中级)机车车辆管道工(中级)题库
题型:填空题

阅读理解.

     My sister,Mary,usually starts the day with breakfast. She often has a piece of cake and a glass of milk

for breakfast, then she usually goes to work on foot. After work, she often goes to the music store.

Sometimes she goes to the movies. She likes eating vegetables. She also likes to eat junk food,but she

knows it is bad for her health. So she eats it once a week. In the evening,she often watches TV. Her

favorite program is Around China. She usually goes to bed before 11 o'clock. She thinks she is pretty

healthy.

1. Mary usually goes to work                 .

A. on foot

B. by bus

C. by bike

D. by plane

2. Her favorite TV program is _______________ .

A. Animal World

B. Game Show

C. Around China

D. Today Law(法律)

3. She eats junk food __________a week.

A. once

B. twice

C. three times

D. two times

4. She _________goes to the movies.

A. never

B. always

C. often

D. sometimes

5. She ___________at 11 0-clock.

A. goes to bed

B. is asleep

C. doesn't go to bed

D. isn't asleep

题型:填空题
已知函数f(x)=cos2
π
2
x
,则使f(x+c)=f(x)恒成立的最小正数c=______.
题型:填空题

下列叙述错误的是(  )

A.乙烯和苯都能使溴水褪色,褪色的原因相同

B.(CH3)2C==CHCH2CH3分子中的六个碳原子中至少有五个在同一个平面上

C.煤油可由石油分馏获得,可用作燃料和保存少量金属钠

D.乙醇、乙酸、乙酸乙酯都能发生取代反应,乙酸乙酯中的少量乙酸可用饱和Na2CO3溶液除去

题型:填空题

如图1中,用大小相同的力作用于弹簧,观察比较两次做法可知力的作用效果与力的______有关;如图2中,用大小相同的力,______(选填“甲”、或“乙”)的握法更利于拧紧或松开螺帽,这说明力的作用效果与力的______有关.

题型:填空题

一条曲线上的任何点,都代表企业在资源给定的条件下能够生产的各种产品最大可能产量的可能组合,那么,这条曲线是()。

A.等产量曲线

B.等成本曲线

C.等收入曲线

D.产品转换曲线

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