汽轮机惰走曲线有说明特点，为什么？

下列耕地中，属于免征耕地占用税的是（）。

A.制药企业占用耕地

B.停机坪占用耕地

C.港口占用耕地

D.医院占用耕地

Which of the following is not used for giving advice? [ ]

A. You had better not watch a horror film since you get scared easily.

B. You mustn't give your goldfish too much food.

C. The swimming pool isn't open today. I don't know where to go swimming.

D. Perhaps you should buy some souvenirs for your parents.

推土机开挖土质路堑作业时�推土机开挖土方作业由切土、运土、卸土、折返、空回等过程组成一个循环影响作业效率的主要因素是（）和运土两个环节。

A.折返

B.卸土

C.切土

在工艺系统刚性好的情况下，刀具有磨钝标准应规定得较（）；精加工时应规定较（）的磨钝标准。

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