外源性抗原是指（）
A.来源于体外的抗原
B.来源于细胞外的抗原
C.由细胞合成的抗原
D.细胞合成后分泌出的抗原
E.APC处理过的抗原
参考答案：B
---Would you like _______ orange juice? ---Yes, please.
A．some
B．any
C． many
D．an
I'm not sorry he's in prison.In my opinion he got what he _____. [ ]
A. preserved
B. deserted
C. deserved
D. reserved
