The problem had become in his mind and he could not decide what to do about it.A. simpli

问题补充：

The problem had become in his mind, and he could not decide what to do about it.

A. simplified

B. exaggerated

C. matured

D. isolated

答案：

A. simplified

B. exaggerated

C. matured

D. isolated

解析：exaggerate(=say or believe more than the truth about sth.)夸张，夸大：It was a rabbit, not a lion. You are exaggerating as usual. (这是一只兔子，不是狮子。你经常夸大事实。)simplify 简化；mature使成熟；isolate使孤立。

本题译文：这个问题在他头脑里夸大了，因此他无法决定该怎么办。