【题目】The parents were shocked by ______ news that their son needed ______ operation on his knee.
A.A; /
B.the; /
C.the; an
D.a; an

【答案】C
【解析】句意：家长们听到他们的儿子需要在膝盖上做一个手术这个消息，很震惊。此句中的news是特指后面同位语从句中提到的内容，故应该用定冠词the；儿子需要在膝盖上做一个手术，非特指，用不定冠词a。，选C。