题目

－What's in the box?－__________ a shirt and two dresses A . There is B . There are C . Have D . Has 答案：A20．一个长方形的周长是42cm，宽比长少3cm，如果设长xcm，宽为ycm，根据题意，列方程组为$\left\{\begin{array}{l}{2（x+y）=42}\\{x-y=3}\end{array}\right.$．