be 动词的用法口诀：
I用am，you用are，is用于他她它；is连着他（he）她(she)它(it)，复数后面都用are。
行为动词第三人称单数的五种变化形式
一、 大多数动词后加s. makes
二、 以ch、sh、s、ss或x结尾的动词后加es.
teaches. finishes，washes , watches
三、以辅音字母 y结尾的动词去掉y,再加ies
carries flies studies
元音 y结尾直接加s
enjoys plays
四、以辅音字母 o结尾的动词后加es.
goes does
五、 特殊变化 。 have ---has
动词的现在分词的构成
1.大多数动词 ing
think → thinking
2.以不发音e 结尾的动词 - e ing
take → taking
3.以ie 结尾的动词 -ie y ing
lie → lying
4.某些以“一个元音字母 一个辅音字母”结尾的动词
双写辅音字母 ing
run → running swim → swimming
get → getting
规则动词的过去式和过去分词的构成
1. verb＋ed 如：visit-visited -visited
2. 以不发音的e结尾，＋d 如：move-moved -moved
3. 双写＋ed（以一个辅音字母结尾的重读闭音节词,
双写最后一个辅音字母＋ed）
如：stop-stopped -stopped
4. 以辅音字母加y结尾的词,去y＋ied.
如：study-studied-studied
不规则变化过去分词的构成
Type original p.t p.p
AAA cost cost cost
ABA come came come
run ran run
get got got
ABB catch caught caught
ABC see saw seen
forget forgot forgotten
drink drank drunk
grow grew grown
eat ate eaten
