从显象管尾部灯丝发射出来的电子，高速撞击在电视机荧光屏上，使

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问题填空题

从显象管尾部灯丝发射出来的电子，高速撞击在电视机荧光屏上，使屏幕发光，则在显象管内（　　）

A．电流的方向从灯丝到荧光屏

B．电流方向从荧光屏到灯丝

C．显象管内是真空，无法通过电流

D．显象管中电流的方向不断改变

答案

由题意可知电子的移动方向为从灯丝到荧光屏，电子带负电，因为电流的方向与负电荷定向移动的方向相反，所以电流方向为从荧光屏到灯丝．

故选B．

补全对话，情景问答

交际运用。根据对话内容，在空白处填写适当的话语（话语可能是一个句子，也可能是一个短语或一个词），使对话完整。

A: Hello, this is Tom. May I speak to Jack?

B: Yes, speaking.

A: Hi, Jack. I called you just now but nobody answered. 1 ?

B: I went to the barber's.

A: 2 ?

B: Yes. Our teacher said teenagers shouldn't have long hair. By the way, why was the teacher 3 you

this morning?

A: Because I called on my cell phone in the hallway. And she took it away. I think that's unfair.

B: That's too bad. But the school has to have rules, you know?

A: Sure. But my mother had a bad cold and stayed at home alone. 4 her, so I called her up.

B: Maybe if you 5 it to our teacher, our teacher will understand.

1. __________ 2. __________ 3. __________ 4. __________ 5. __________

单项选择题

有一耳源性脑脓肿患者，CT证实为右颞脓肿，脓肿腔直径5.5cm，出现昏迷，右瞳散大，采取最佳措施是

A．快速静点甘露醇

B．快速静点甘露醇，并行右颞肌下减压术

C．快速静点甘露醇，并行右颞脓肿穿刺抽脓

D．快速静点甘露醇，并行双侧颞肌下减压术

E．立即行脓肿切除术