金属结构装配中常用的夹具按夹紧力的来源可分为（）两大类。
参考答案：手动夹紧和机动夹紧
Be careful! The traffic light is red. You mustn't go ______ the street now. [ ]
A.on
B.in
C.along
D.across
i5T5系列智能车床可以达到的加工精度为IT几级？
