The three children looked after their sick mother__

问题描述:

The three children looked after their sick mother__
A.in return B.by turn C.in turn D.being done
百思不得其解
但是in turn是解作轮流啊。怎么不是轮流照看母亲而是照看母亲作为回报呢?

A.in return --------------作为回报,作为报答