第21题: [填空题]A on the plane B at the bank C at the airport D at the office E at the theatre F at the hotel G at the customs H on the bus 参考答案:C 答案解析:[解析] Woman: It’s too bad that our flight is delayed for an hour. Our plane is supposed to leave
第32题: [单项选择]可燃性混合物的爆炸极限范围越宽,则发生爆炸的危险性( )。 A. 越小 B. 越大 C. 无关 D. 无规律 参考答案:B 答案解析:爆炸极限越宽,可燃物(可燃气体.蒸气或粉尘)发生爆炸的概率就越高,爆炸的危险性越大,如乙炔与空气混合的爆炸极限为2.2%~81%,氨和空气混合的爆炸极限为15%~28%,显然乙炔的爆炸危险性比氨的爆炸