Jack is ill, so we’ll have no choice but to give the performance ______ him.

A．except for

B．apart from

C．except

D．without

光合势是（）二者的乘积。

A、比叶面积

B、群体绿叶面积

C、群体总叶面积

D、叶面积指数

E、叶面积持续期