联轴器找中心时,根据测量结果,记录在如图中,由此求出中心偏差值,当时,则()。 A、

题型:单项选择题

问题:

联轴器找中心时,根据测量结果,记录在如图中,由此求出中心偏差值,当时,则()。

 

A、上下张口;

B、高低位移;

C、左右张口;

D、左右位移。

考点:水泵检修工考试水泵检修工考试题库
题型:单项选择题

如图所示,在光滑的水平面上宽度为L的区域内,有一竖直向下的匀强磁场.现有一个边长为a (a<L)的正方形闭合线圈以垂直于磁场边界的初速度v0向右滑动,穿过磁场后速度减为v,那么当线圈完全处于磁场中时,其速度大小(  )

A.大于

B.等于

C.小于

D.以上均有可能

题型:单项选择题

如图是“雨的形成”实验装置,用酒精灯将烧瓶内的水加热沸腾后,水蒸气从细玻璃管口喷出,在离管口稍远处,可以看到雾状的“白气”。如果这时在管口处放置一块玻璃片,会发现正对管口的玻璃片表面有_______,玻璃片的温度将_________(选填“升高”、“降低”或“不变”)。我国是水资源严重缺乏的国家,节约用水应从我做起,请你写出日常生活中的一项节约用水措施:                          

题型:单项选择题

四、阅读理解(2分×15=30分)阅读下列短文,从每题所给的A、B、C和D项中,选出最佳选项。

Talk about a real-life hero! Ten-year-old Larry Champagne from St. Louis,Missouri, hit the brake (刹车) on a runaway school bus. He saved himself and 20 other kids on board from disaster.

It all happened in one terrible accident. On the way to school, the bus driver, Ernestine Blackman, suddenly fell ill. Seeing the car was running away, the other kids started to scream, but Larry ran to the front and stopped the bus.

“At first I thought, ‘We’re going to die,’” says Larry, “but after I pressed the brake, I felt safe.”

Larry’s speedy reaction made news all over the country. He appeared on TV shows as a hero. The bus company gave Larry a big gift. His school hung a medal of honor around his neck.

“My grandmother always tells me to do what’s right,” says Larry. He thanked his brother, Jerrick, 9, who “helped me get the bus driver up” during the emergency(紧急情况). How did he know how to stop the bus? Larry is something of a mechanic(机械师). He helps his grandfather work on his old truck. “He gets his hands dirty,” says his grandfather. One thing is for certain: Larry knows where to find the brakes.

1. What did Larry do to save the runaway bus?

A. He parked it for the sleeping bus driver. 

B. He helped all the kids climb out through the windows.

C. He dialed 911.              D. he pressed the brake.

2. When did Larry finally feel safe?

A. When the kids finally stopped screaming.        B. When the police officers arrived.

C. Once he pressed the brake, and the bus stopped.   D. When the bus driver started driving again.

3. Larry got the following as praise for his hero action Except            .

A. appearing on TV shows                         B. a scholarship from his school

C. a big gift from the bus company                    D. a medal of honor

4. Larry thanked his brother Jerrick for             .

A. helping him get the bus driver up                  B. helping him work on his old truck

C. teaching him how to find the brake         D. teaching him how to stop the bus

5. The underlined sentence“Larry is something of a mechanic” tells us that               .

A. Larry’s job is a mechanic                       B. Larry knows something about machines

C. Larry is a robot                                     D. Larry knows nothing about machines

题型:单项选择题

5岁儿童,易烦躁、异食癖、面色苍白、血红蛋白100g/L,红细胞游离原卟啉升高,最可能的疾病是()

A.蛋白质缺乏症

B.锌缺乏症

C.缺铁性贫血症

D.地中海贫血症

E.巨幼细胞贫血症

题型:单项选择题

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