问题
单项选择题
用立钻在分度头上进行圆周分度钻孔应将分度头（）回转到水平位置的零位。
A.分度叉
B.定位销
C.主轴
D.分度盘
答案
参考答案：C
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用立钻在分度头上进行圆周分度钻孔应将分度头（）回转到水平位置的零位。
A.分度叉
B.定位销
C.主轴
D.分度盘
参考答案：C
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| Many students have hobbies, such as 1 , painting, growing vegetables in their gardens, or looking 2 animals. Some hobbies are relaxing and 3 are creative. 4 can make you grow as a person, develop your interests and help you learn new skills. David Smith is a student. His hobby is 5 . In senior high school, he wrote a book and it 6 out in 2003. Many teenagers love his book. 7 a result,David has become a successful young 8 . In spite of his great success, David sees writing as only one of 9 many hobbies and interests. "I like playing badminton, too." says David. He isn't sure 10 he is going to write more books in the future. David is very lucky 11 his hobby has brought him 12 and success.But he is 13 in many other things, and he spends time playing badminton for his school team. 14 is something difficult to remember that we shouldn't 15 all our time on our favorite hobby. There are many other interesting things to do in life, and we should try to do something new or difficult. | ||||
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