呕血最常见的疾病是（）。

A.胃底及食管静脉曲张破裂

B.慢性胃炎

C.消化性溃疡

D.急性胃黏膜病变

E.肠憩室病

Frequently single-parent children ________ some of the functions that the absent adult in the house would have served.

A．take on

B．take up

C．take in

D．take after