防爆门的作用：当井下一旦发生爆炸事故时，防爆门被爆炸的气流冲击而打开，起到泄压作用以保护主要通风机。（）
参考答案：对
两个连续自然数的和是奇数．______．
He had planned to make a compromise, but ______ he changed his mind at the last minute.
A．therefore
B．somehow
C．anyhow
D．otherwise
