合成塔外壳温差过大是因为冷激气阀开度过小。
参考答案：错
解析：合成塔外壳温差过大是因为主进气阀开度过小。
在浇铸铝镇静钢时，应选择碱度低、粘度较高的保护渣。
To keep Chinese economy going on, the government has established an employment service system for ____ jobless urban residents.
A．badly off
B．well off
C．cut off
D．paid off
