问题
单项选择题
具有良好的抗水性能,可在-60~150℃的温度范围内使用,且化学稳定性好,非常适用于高速和精密的滚动轴承的润滑的润滑脂是()润滑脂。
A、钙基
B、锂基
C、钾基
D、三硫化钼
答案
参考答案:B
具有良好的抗水性能,可在-60~150℃的温度范围内使用,且化学稳定性好,非常适用于高速和精密的滚动轴承的润滑的润滑脂是()润滑脂。
A、钙基
B、锂基
C、钾基
D、三硫化钼
参考答案:B
阅读理解.根据材料内容,选择最佳选项 | |||||
Here are five points you can follow to improve your English, and the first point is the most important.
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1. Point _____ is more important than any other point. | |||||
A. No. 1 B. No. 2 C. No. 4 D. No. 5 | |||||
2. According to the passage, an English learner should study _____ every week to make good progress. | |||||
A. about two hours B. at least four hours C. at least five hours D. more than seven hours | |||||
3. The underlined word "subtitles" means "_____" in Chinese. | |||||
A. 情节 B. 字幕 C. 画面 D. 人物 | |||||
4. Which of the following activities is NOT mentioned (提到)? | |||||
A. Reading English books. B. Singing English songs. C. Watching English films. D. Writing e-mails in English. | |||||
5. The reading above is mainly about _____. | |||||
A. how to improve your English B. why we need to learn English C. how to study English for pleasure D. how we can sing English songs well |