金属切削加工中的振动主要有()、()两种类型。
参考答案:受迫振动;自激振动
---Could you please give the dictionary to Wang Feng?
---Yes, of course! I’ll give it to him ________ he comes back.
A.since
B.before
C.as soon as
D.until
1978年党的十一届三中全会初步提出了改革开放的方针。