重难点二 动词过去式的不规则变化
解析 常见的动词过去式的不规则变化有：
不规则变化的方式 示例 不规则变化的方式 示例
元音字母i改为a/o sing—sang，drive—drove ell改为old sell—sold，tell—told
元音字母o/u改为a become—became，run—ran an改为oo stand—stood，understand—understood
元音字母e改为o get—got，forget—forgot know—knew，draw—drew
ee改为e meet—met，feed—fed 动词原形与过去式同形 read(/riːd/)—read(/red/)，hurt—hurt，fit—fit(fitted也可)
eak改为oke break—broke，speak—spoke ought型 bring—brought，buy—bought
eep改为ept sleep—slept，keep—kept aught型 teach—taught，catch—caught
[典例剖析] 用所给词的适当形式填空。
1. Everyone danced and (sing) happily at her birthday party.
2. The next day, Mr Smith (go) out and never came back.
点拨 第1小题，and连接的前后两个动词在时态上要保持一致，由danced可知，sing要用其过去式sang，故填sang。第2小题，由The next day和came可知，此句的时态是一般过去时，谓语动词go要用其过去式went，故填went。
[反馈练习] 写出括号内动词的过去式，并给下列句子排序，使之成为一个完整的故事。
()He (go) to the field every day to see the seedlings(秧苗). He wished that the seedlings in his field could grow quickly.
( 1 )Long ago, there (be) a farmer. He planted a lot of rice in his field.
()He (think) about this day and night, but the seedlings still (grow) slowly. “I have to find a way to help them grow fast,” he (say).
()One day, he (have) an idea and (run) to the field. He pulled(拔) his seedlings up one by one.
()His son (hear) about this and ran to the field. However, all the seedlings (die).
()He was tired after doing this for a whole day. But he (feel) very happy because he thought the seedlings would grow a lot.