石油工业常用的灭火物质有：（）、水、（）、惰性气体、不燃性挥发液、固态物质。
参考答案：灭火泡沫、化学干粉
最大可能是哪种疾病
A．右侧结肠癌
B．肠结核
C．克罗恩病
D．溃疡性结肠炎
E．血吸虫病性肉芽肿
_____ we were worried about was _____ they could manage to control the pollution. [ ]
A. That; how
B. What; whether
C. That; whether
D. What, that.
