桩冠预备，根尖部一般应该保留填充材料的长度为（） A.2～3mm _爱下问搜题

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问题单项选择题 A1/A2型题

桩冠预备，根尖部一般应该保留填充材料的长度为（）

A.2～3mm

B.0~2mm

C.3~5mm

D.5~7mm

E.不保留

答案

参考答案：C

选择题

在空间某一点以大小相同的速度分别竖直上抛、竖直下抛、水平抛出质量相等的小球，不计空气阻力，经过ts（设小球均未落地）则（　　）

A．做上抛运动小球动量变化最大

B．做下抛运动小球动量变化最小

C．三个小球动量变化大小相等

D．做平抛运动小球动量变化最小

填空题

either, his, each, it, something, another, any, himself, both, all, that

1. He _____ is very careless. He always makes such mistakes.
2. —This sweater is much too large for me. Could you show me_____one?
   —Sure. Just a minute.
3. The old man lived here _____his life.
4. _____of the rooms can hold twenty people.
5. These boxes are heavier than _____ on the desk.
6. _____can stop the boy from giving up the chance to interview.
7. —When shall we play chess again?
    —_____day is OK. I'm free all the week.
8. The two kinds of paper are_____good. You can take _____of them.
9. —Is this your son's coat?
    —No. _____is on the chair behind the desk.
10. I find _____ necessary to tell her about this matter.