低温退火的目的是在提高塑性的同时，并需部分保留由冷变形而获得的（）状态。
参考答案：冷作硬化
46.It's no use___________over spilt milk.
47.
A．cry
B．crying
C．that you cry
D．for you to cry
— Excuse me, is this seat _____?
— Yes, it's available.[ ]
A. vacant
B. bare
C. blank
D. occupied
