—I worry about ______ enough time and energy to finish that job.

—Don’t worry about it. I’ll help you!

A．not having

B．not have

C．didn’t have

D．don’t have

一级动力学的特点在于（）

A.一级速率常数不随体内药物浓度的变化而改变

B.不同剂量的给药具有相同的半衰期

C.属于被动转运

D.属于主动转运

E.一级速率常数随体内药物浓度的变化而改变