1.Helping animals _____ helping people.

问题描述:

1.Helping animals _____ helping people.
A.is B.are C.am D.can
2.The students helped _____ the park yesterday.
A.clean up B,cleaning up C.cleans D.cleaned
要说明原因

第一题A,helping animals是动名词担当主语,是单数形式,后面接的是动词现在分词,所以用is
第二题,A,记住,help sb (to)do sth.to可以省略,但动词一定是原形的!