喷煤喷吹中无烟煤配入量达（）时混合煤粉的爆炸性可消除。
A、10％－20
B、30％－40％
C、40％－50％
D、50％－60％
参考答案：C
He has learned , no matter what happens and how bad seems today, life goes on and it will be better tomorrow.
A．that; it
B．it; that
C．it; it
D．that; that
烷化剂类化疗药（）。
A.环磷酰胺
B.放线菌素
C.VCR
D.三苯氧胺
E.甲氨蝶呤
