March is a Civility month(文明礼貌月) in China. More and more young people are trying to do all

问题补充：

March is a Civility month(文明礼貌月) in China. More and more young people

are trying to do all they can the elderly.

A. helped

B. to help

C. help

D. helps

答案：

A. helped

(答案→)B. to help

C. help

D. helps

解析：动词不定式可以用在谓语后面，表示一次性的动作，说明动作的方向目的等，此处帮助老人是他们做事的目的，所以选B，努力去做他们能做的来帮助老人们。