金属材料退火的目的是什么?
参考答案:
金属材料退火的目的主要是:降低硬度以利切削加工,细化晶粒,均匀组织,改善钢的机械性能,消除钢中的内应力,提高钢的塑性和韧性。
根据对话内容,从对话后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
—Excuse me, can you tell me where the nearest restaurant is?
—____1____
—Where is the nearest restaurant, please?
—Oh, the restaurant? The nearest one is the City Restaurant. ___2___
—I‘m ——er—— I’m afraid I don‘t quite ……you see, ____3____
—I see. Simply walk two blocks straight ahead, then turn left, and the City Restaurant is about 10 metres ahead. ____4____
—Can I take a bus?
—Of course you can. but ____5____ It‘s only a few minutes’ walk.
—Thank you very much.
—Not at all.
A.What did you say?
B.I‘m a total stranger here.
C.You can‘t miss it.
D.I beg your pardon?E. It‘s just opposite the No. 5 Department Store.
F. I don‘t think it is necessary.
G. It‘s not very far.
如果一台主机的IP地址为20.22.25.6,子网掩码为255.255.255.0,那么该主机所属的网络(包括子网) 为( )。
A.20.22.25.0
B.20.22.0.0
C.20.0.0.0
D.0.0.0.0