如图所示,弹簧秤和细绳重力不计,不计一切摩擦,物体重G=5N,弹簧秤A和B的读数分别为
A.5N,0N
B.5N,10N
C.5N,5N
D.10N,5N
答案:C
What are you doing? [ ]
A. We are listening to the music.
B. We go to the park in the morning.
检查刮削精度常用哪些方法?