It seemed that our nursery rhymes___ some magic because all the nights I sang them for my daughter, she would listen to them with keen pleasure．

A．must have had

B．should have had

C．could have had

D．need have had

治疗血虚证时配伍补气药的理论依据是（）

A.气能生血

B.气能行血

C.气能摄血

D.血能载气

E.血能养气