- are you?
-I'm sick.[ ]
A. Who
B. What
C. How
答案:C
人力制动机踏板或支架弯曲、变形时调修,裂纹、腐蚀严重时更换;组装螺栓须紧固后()。
A.紧固
B.焊固
C.点焊