采用煤气燃料时，应设置（）及与煤气低压讯号联锁的（）等防回火设施。
参考答案：煤气低压报警；快速切断阀
一张5元，一张2元，一张1元，一张5角合起来是______元．
We need _______ performers to sing this song. [ ]
A. more some
B. some more
C. another more
D. more another
