英语翻译

题目

英语翻译
Thier parents had a lot of trouble _____ the dolls because there were so few.
A buy B buying Cto buy D bought

答案

正确答案:B
(这里用到的句型是have trouble in doing sth.,in 在这里省略.
Their parents had ...,因为是过去式,所以这里用have的过去式had .)