补体激活的经典途径和替代途径的交汇点是（）
A.C2
B.C3
C.C4
D.C5
E.C7
参考答案：B
蛋白质-热能营养不良小儿，实验室检查最突出的表现是（）
A.血清白蛋白浓度降低
B.必需氨基酸浓度降低
C.血浆胆固醇浓度降低
D.微量元素浓度降低
E.低血糖
He had to ___________ smoking because of his illness. [ ]
A. get up
B. put up
C. pick up
D. give up
