—Bill hasn’t paid for the school things, has he?

—     . Her mother will pay for them.

A．Yes, he has

B．No, he hasn’t

C．Yes, he did

D．No, he didn’t

诱导髓样干细胞向红细胞分化的主要细胞因子是()

A．IL-3

B．GM-CSE

C．IL-7

D．G-CSF

E．EPO