【判断题】划分加工阶段可以合理使用机床设备,粗加工可采用功率大、精度一般的机床设备,精加工用相应精密机床设备,这样能充分发挥机床的性能特点
【单选题】A person pulls a box across the floor. Which is the correct analysis of the situation?
A.
1. The box moves forward because the person pulls forward slightly harder on the box than the box pulls backward on the person.
B.
Because action always equals reaction, the person cannot pull the box- the box pulls backward just as hard as the person pulls forward, so there is no motion.
C.
The person gets the box to move by giving it a tug during which the force on the box is momentarily greater than the force exerted by the box on the person.
D.
The person’s force on the box is as strong as the force of the box on the person, but the frictional force on the person is forward and large while the backward frictional force on the box is small.
E.
The person can pull the box forward only if he or she weighs more than the box.
【单选题】Which floor was hit by the second jet?
【单选题】亚硝酸钠滴定法测定时,一般均加入溴化钾,其目的是( )
【单选题】The book which is lying on the floor is mine.
【单选题】The floor which ______ pieces of paper is dirty.
【单选题】2018年的中央1号文件,颁布了2018------?乡村振兴规划实施纲要( )