B细胞特有的表面标志（）
A.CD4
B.CD8
C.CD20
D.CD3
E.CD19
参考答案：C, E
He has got himself into a dangerous situation ______ he is likely to lose control over the plan.[ ]
A. when
B. which
C. where
D. why
运输合理化的途径是什么？
