铸坯表面不常见缺陷有（）。
A.裂纹
B.气泡
C.耳子
参考答案：C
--- What do you think of the fish? --- It looks __________,but tastes__________.
A．good; bad
B．well; bad
C．well; badly
D．good; badly
绕线转子异步电动机双反馈调速有哪五种工况？
