A.30s B.45s C.1min D.2min
A.軸頸 B.防塵板座 C.軸中央 D.輪座
A.會(huì)引起熱切軸 B.不會(huì)發(fā)生熱切軸 C.會(huì)導(dǎo)致冷切軸 D.不會(huì)切軸