–What did your parents think about your decision?
–They always let me do I think I should.
A. when
B. that`
C. how
D. what
网友回答
A. when
B. that`
C. how
(答案→)D. what
解析：what（表示关系）（所）……的.Everyone should do what he thinks right.每个人都应该做自己认为是正确的事情。此外I think作插入语。