Question

—My son is lost . Have you seen a boy passing by here?
—I saw        boy hidden behind          tree over there . You may go and have a look.

A．a; the

B．the; the

C．a; a

D．the; a

Answer 1

A

第一个空用不定冠词表示后者曾见过一个男孩，不一定是问话者所要找的；第二个空为特指，表示“那儿的那棵树”，用“the”.故选A