与Ⅱ型超敏反应的主要抗体为()
A.IgA
B.IgE
C.sIgA
D.IgG和IgM
E.IgG重链
参考答案:D
He usually plays _____ piano on Saturdays and plays _____ tennis on Saturdays.[ ]
A. the; a
B. the: the
C. /; the
D. the; /
I'm sorry I didn't phone you, but I've been very busy _____ the past couple of weeks. [ ]
A. beyond
B. with
C. among
D. over