对于外形小且壁厚有一定顺序的工件,一般采用单支水线。
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They ___ do well in the exam.
A. can be able to
B. be able to
C. can able to
D. are able to
-May I take this book out? -No, you___.
A. can't
B. may not
C. needn't
D. aren't
-He___ be in the classroom, I think. -No, he ___ be in the classroom. I saw him go home a minute ago.
A. can; may not
B. must; may not
C. may; can't
D. may; mustn't
-Shall I get one more cake for you, Dad? -Thanks, but you___, I've had enough.
A. may not
B. must not
C. can't
D. needn't
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