being nice to people is almost like helping them

题目

being nice to people is almost like helping them
Be为什么要加ing

答案

看句子成分就知道为什么了!
being nice to people（动名词短语做主语） is（系动词） almost like helping them（介词短语作表语）
要做主语,动词得用V-ing,或者To do sth 的形式,即“动名词”或者“不定式”