----What did you see on the large farm last Sunday?

----Oh, I saw about three ________ hens and _________ of eggs.

A．hundred; hundreds

B．hundreds; thousands

C．thousands; thousand

D．hundred; thousand

黄铜气焊后，焊缝应在600~650℃的温度下进行退火处理，且处理部分不小于5北的焊缝。