—Linda, together with her parents, up the mess in the park at the moment.
—It’s meaningful to be a volunteer. Let’s join them.
A. is cleaning
B. are cleaning
C. has cleaned
D. have cleaned
网友回答
(答案→)A. is cleaning
B. are cleaning
C. has cleaned
D. have cleaned
解析：此题考查主谓一致问题，her parents 是从属结构，真正的主语是Linda，故谓语动词用单数。