His younger sister may already be in high school now, in ________ case this picture book is too childish for her.

A．that

B．which

C．whose

D．what

下列哪一种药物易穿过血脑屏障（）

A.头孢氨苄

B.氯霉素

C.红霉素

D.青霉素

E.阿克米星（丁胺卡那霉素）