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问题 单项选择题

恩氟烷挥发罐开至2%，新鲜气流量为7L/min时，1小时约消耗恩氟烷（）

A.42.5ml

B.52.5ml

C.62.5ml

D.72.5ml

E.82.5ml

答案

参考答案：A

补全对话，情景问答

根据对话内容，在空白处填入一个适当的句子，使对话完整、正确。

A:  Li Na, the summer vocation is coming. What are your plans?

B:  I am going on a visit to Wuhan with my parents by train.

A:  (1)________?

B:  No, I haven't. I'll do it at once.

C:  Hello! Enshi Railway Station. (2)________?

B:  I'd like to book some tickets to Wuhan at 8:00a.m on July 1st. (3)________?

C:  We have tickets at ￥145 for the hard sleeper and￥232 for the soft sleeper. Which kind do you want?

B:  (4)________.

C:  All right. Three soft sleeper tickets. Please pay for the tickets before 6:00a.m. (5)________?

B:  Sure. I'm Li Na and my telephone number is 8410555. Thank you.

C:  You're welcome.

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单项选择题

如图8所示，分别为mA、mB的A、B两物块用轻线连接放在倾角为θ的斜面上，用始终平行于斜面向上的恒定拉力F拉A，使A、B沿斜面向上一起做匀加速运动，A、B与斜面的动摩擦因数均为μ，为了增大细线上的张力，下列办法可行的是（）

A.仅增大A的质量mA

B.仅增大B的质量mB

C.仅增大斜面倾角θ（F仍平行于斜面）

D.仅增大动摩擦因数μ
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