Our school-run factory _____ various kinds of chemical devices last year.
A. turned into
B. turned up
C. turned out
D. turned off
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Smoking is not good _____ you because it can affect your health.
A. for
B. at
C. to
D. on
在标准双极工艺中,发射区电阻常用做()和()。在单层金属工艺中广泛用做隧道。
对于形状复杂的锻件,为使坯料能合理分布和便于充满模锻模膛,必须让坯料预先在制坯模膛内锻压制坯。()