The parents were in search their son who was lost when the two countries were war.
A. of; in
B. of; at
C. for; at
D. for; in
网友回答
A. of; in
(答案→)B. of; at
C. for; at
D. for; in
解析：考查固定词组。固定词组in search of 寻找…；at war在战争时；句意：当这两个国家处于战争状态的时候，这对父母正在寻找失踪的的儿子。故B正确。