A.N+2 B.N+1 C.N+1或N+2 D.N+1和N+2
A、0.04%～0.06% B、0.06%～0.10% C、0.10%～0.14%
A.用家中座机电话报燃气公司 B.开窗通风 C.关闭煤气阀门 D.疏散家人到外面
A.< B.> C.= D.≤
