每题的备选项中,只有1个最符合题意。
矿山粉尘(煤矿煤尘)爆炸必须同时具备( )个条件。
A.3
B.4
C.5
D.6
参考答案:B
.Not only_________everything he had taken away from him,but also his citizenship.
A.has
B.had
C.was
D.is
人字桅杆又称为人字架、两木杆和两木搭,它是由两根圆木或无缝管交叉捆绑人字形而成。