The Canadian friends from our school have given us a lot of books, few of______ a bit difficult for us Chinese students.

A．them are

B．that is

C．which are

D．which is

下列阑尾炎病理特征与临床分型哪项是的

A．阑尾周围脓肿
B．坏疽及穿孔性阑尾炎
C．急性化脓性阑尾炎
D．急性单纯性阑尾炎
E．非典型阑尾炎