能引起肠源性青紫症的是（）
A.组胺
B.亚硝酸盐
C.有机磷
D.砷
E.苯
参考答案：B
I'd like to help____ the box[ ]
A. she carry
B. he to carry
C. her carry.
D. her carrying
GGH蒸汽吹灰启动条件有哪些？
