A good storyteller must be able to hold his listeners’ curiosity__________he reaches the end.

A．when

B．unless

C．after

D．until.

口服铁剂治疗有效的缺铁性贫血患者，下列化验最先上升的是（）

A.网织红细胞

B.血红蛋白

C.MCV

D.MCH

E.MCHC