超分割放疗中为使正常组织有充分的时间恢复，两次放疗的间隔时间需在（）以上。
A.2小时
B.4小时
C.6小时
D.8小时
E.10小时
参考答案：C
. — Do you think there is anything ____ interest in the exhibition?
— Yes, I think some of the pictures are ____.
A．for; of help
B．of; of great help
C．in; of helpful
D．at; helpful
简述西洋参的功效与作用。
