They often leave the boy alone at home. They think that he’s old enough to look after .A.

问题补充：

They often leave the boy alone at home. They think that he’s old enough to look after .

A. them

B. himself

C. themselves

D. him

答案：

A. them

(答案→)B. himself

C. themselves

D. him

解析：

本题考查的是反身代词的用法。句意是说他们认为他足够大了能够照顾他自己，故用himself，选B。