—Come in Peter, I want to show something to you.

—Oh, how nice of you! I______ you ______to bring me a gift.

A．never think; are going

B．never thought; were going

C．don’t think; were going

D．hadn’t thought; were going

具有特异性肿瘤细胞杀伤活性的是（）

A.CTL

B.NK细胞

C.嗜中性粒细胞

D.嗜碱性粒细胞

E.单核细胞