规则变化：新|课 | 标|第 |一| 网

1. 一般在动词词尾直接加ed。如：pick → picked → picked; wish → wished → wished; stay → stayed → stayed

2. 以不发音的e结尾的动词后面加d。如：like → liked → liked; hope → hoped → hoped; phone → phoned → phoned

3. 以"辅音字母 + y"结尾的动词，变y为i，再加-ed。如：study → studied → studied; hurry → hurried → hurried; reply → replied → replied

4. 词尾只有一个辅音字母的重读闭音节动词，要双写辅音字母，再加-ed。如：stop → stopped → stopped; clap → clapped → clapped

不规则变化：

5. 以不变应万变。如：let → let → let; put → put → put; read → read → read

6. 若中间有双写e，则去掉一个e，单词末尾再加t。如：feel → felt → felt; keep → kept → kept; sleep → slept → slept

7. 结尾的字母d变t。如：lend → lent → lent; build → built → built; send → sent → sent

8. 变为以-ought或-aught结尾。如：buy → bought → bought; bring → brought → brought; catch → caught → caught; teach → taught → taught

句式

1. 肯定句：主语 + have / has + 过去分词 (+ 其他)

2. 否定句：主语 + have / has + not + 过去

分词(+ 其他)

3. 一般疑问句：have/ has + 主语 + 过去分词(+ 其他)

1) 特殊疑问词 (不是句子主语) + have / has + 主语+过去分词 (+ 其他)

2) 特殊疑问词(是句子主语)+have / has+过去分词(+ 其他)

already和yet都可以作为现在完成时的标志词，但它们的用法不同。

◆already一般用于肯定句中。如：

We have already cleaned up our classroom.

注意：already用于疑问句中时通常表示惊奇。如：

Have you finished your homework already? I can't believe it.