Jack is good, kind, hard-working and intelligent. _____, I can’t speak too highly of him.

A．As a result

B．By the way

C．On the whole

D．In a word

对母体与胎儿间的体内物质和药物交换起着重要作用

A．胎盘屏障
B．血脑屏障
C．药物-蛋白结合
D．首过作用
E．pH分配假说