肝肠循环是（）。
首过消除是（）。

A.弱酸性或弱碱性药物解离常数

B.弱酸性或弱碱性药物解离常数的负对数

C.口服药物吸收时首次通过肝脏经转化而使进入体循环的药量减少

D.收入血的药量

E.药物随胆汁排泄到达小肠后被重新吸收的过程

—How is your son's English, Mr. Liu?  

—I think something must be done _______. [ ]

A. to cheer him up

B. to cheer up him

C. cheer him up

D. cheer up him