以下不是NK喷油件常见的不良缺陷()。
A.色差
B.短射
C.针孔
D.以上均不是
参考答案:B
—Tony, ______?
—I am looking for my camera.[ ]
A. what's up
B. what are you up to
C. how are you
D. are you okay
简述维C的用途。