问题
单项选择题
在边界润滑中，边界油膜的厚度一般约为（）。
A.1mm
B.0.5μm
C.0.1μm
D.0.5mm
答案
参考答案：C
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在边界润滑中，边界油膜的厚度一般约为（）。
A.1mm
B.0.5μm
C.0.1μm
D.0.5mm
参考答案：C
| 选择句子补全对话。 | |
Sarah: She is at home. Teacher: ___________________________________________________________________________ Sarah: She is sick. She has a cold. Teacher: ___________________________________________________________________________ Sarah: Yes, she has a headache. Teacher: ___________________________________________________________________________ Sarah: Yes, she did. And the doctor asked her to take some medicine and stay in bed for one day. Teacher: Oh, ________________. I hope she will be better soon. |