when spring come,all the trees are green.come后面+s吗..

when spring come,all the trees are green.come后面+s吗..
when spring come,all the trees are green.come后面+s吗..

when spring come,all the trees are green.come后面+s吗..
对的 一定加 因为spring是单数 且这句话是客观真理 所以要加

加