动词的第三人称单数形式（简称单三式）
1．一般在词尾加“-s”help-helps make-makes ride-rides know-knows
2．在s z x sh ch 结尾的词在词尾加“-es”push-pushes pass-passes watch-watches wash-washes
3．以“
元音字母＋y”结尾时，加“-s”；以“
辅音字母＋y”结尾时，变 y为i，再加“-es”play-plays stay-stays study-studies carry-carries4．以“辅音字母＋o”结尾的词，多数在词尾加“-es”go-goes do-does
5．be动词的单三式为is 6．have动词的单三式为has
(本文源自轻松英语行
http://englearn.zhan.cn.yahoo.com,转载请注明出处)
补充
:
不定式的省略: Wil you join us? 你要同我们一道去吗？
I should love to (join you). 我愿意。
The boy wanted to ride his bicycle in the street but his mother told him not to.那个男孩想要到街道上骑自行车，但是他的妈妈叫他不要去。
Alice, why didn't you come yesterday? 爱丽斯，你昨天为什么没来？
I was going to, but I had an unexpected visitor. 我本来是要来的，但是家里突然来了一个客人。