识别抗原抗体复合物的补体是（）
A.C1q
B.C1r
C.C1s
D.C2
E.C1qrs
参考答案：E
.
Government should adopt laws that would ban advertising and other types of________of tobacco products.
A．delivery
B．spread
C．promotion
D．discount
中性点不接地系统中发生单相接地时，可继续工作吗？
