Mr. White, along with his assistants, ______ on the project day and night to meet the deadline.

A．work

B．working

C．is working

D．are working

表示药物在体内代谢、排泄的速度的是（）

A.清除率

B.清除速度常数

C.半衰期

D.清除百分数

E.AUC