下列关于电池的说法中正确的是（） A．汽车里通常使用的是

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问题选择题

下列关于电池的说法中正确的是（　　）

A．汽车里通常使用的是干电池

B．干电池有正、负极，而蓄电池不分正、负极

C．电源就是电池

D．手电筒里用的是干电池

答案

A、汽车里通常使用铅蓄电池，故A错误；

B、干电池和铅蓄电池都有正负极，故B错误；

C、电池是电源的一种，故C错误；

D、手电筒一般用的是干电池，故D正确．

故选D．

阅读理解

根据对话内容，从对话后的选项中选出能填入空白处的最佳选项。并在答题卡上将该项涂黑。选项中有两项为多余选项。

W: Hi, John.

M: Hi. Lucy. 1

W: Yes. I'm required to tell a story in English before the lesson begins.

M: Oh, I see. 2

W: You're right. I need to practice on the stage before they all come.

M: 3

W: Yes, here, in my pocket...Oops, where is it?

M: Don't worry, 4

W: ...No, not in the bag either. I'm afraid I left it at home.

M: 5

W: Aha! It's just the key to the classroom! Thank you so much.

A．Glad to see you.

B．What's the story about?

C．What's that around your neck?

D．Maybe you put it in your schoolbag,E. Do you have the key to the classroom?

F. You're going to school rather early today.

G. So you want to get to the classroom earlier to make some preparations?

问答题简答题

简述内啮合转子式油泵的工作原理。