我一直纳闷你是如何靠那点收入过日子的。

A.I’m thinking how do you live on your small income.

B.How you manage on your small income is a puzzle to me.

C.I’m puzzled how could you live withthe little salary.

D.I’m puzzled how could you live by the little salary.

正确答案：How you manage on your small income is a puzzle to me.