暂无配套精讲视频，请阅读右侧笔记。
| 原型 (do) | 过去式 (did) | 过去分词 (done) | 现在分词(doing) |
|---|---|---|---|
| dream | dreamed | dreamed | |
| dreamt | dreamt | ||
| travel | traveled | traveled | traveling |
| travelled | travelled | travelling | |
| throw | threw | thrown | |
| cost | cost | cost |