焦炉煤气中主要的可燃性气体是（）。
A.甲烷
B.二氧化碳
C.氢气
D.乙烷
参考答案：C
—Were there any banana trees in your hometown (家乡).
—________. [ ]
A. No, there weren't
B. Yes, there weren't
C. No, there were
D. Yes, there was
充分发挥大脑功能的措施是（）。
A.信息刺激，勤于用脑
B.协同开发，全面塑脑
C.劳逸结合，科学护脑
D.营养健身，合理补脑
