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【单选题】
渐开线齿轮啮合的主要特点是（）。
A.
保持恒定的传动比，具有传动的可分离性
B.
保持恒定的传动比，传动精度高
C.
保持恒定的传动比，传动效率高
D.
传动比大，传动效率高
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Passage 3 Questions 11 to 15 are based on the following passage: Scientists in India have invented a new way to produce electricity. Their invention does not get its power from oil, coal or other fuel...
A.
Because bullocks have long been used by Indian people
B.
Because bullocks walk slowly and are easy to control.
C.
Because there are few non-working bullocks in India
D.
Because there is not enough oil in India.