P.112 2. Rewrite the sentence using the words in brackets.
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P.110 6Read the article again and comlete the sentences.
P.112 2 Complete the sentences
P.112 1. Match the phrases with the definitions.
下列不属于棘轮机构优点的是__________。
A. 结构简单、制造方便
B. 运动可靠
C. 转交可根据需要进行调节
D. 工作平稳、无噪声
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