| I | undo |
|---|---|
| you | undo |
| he/she/it | undoes |
| we | undo |
| you | undo |
| they | undo |
| I | undid |
|---|---|
| you | undid |
| he/she/it | undid |
| we | undid |
| you | undid |
| they | undid |
| I | have | undone |
|---|---|---|
| you | have | undone |
| he/she/it | has | undone |
| we | have | undone |
| you | have | undone |
| they | have | undone |
| I | had | undone |
|---|---|---|
| you | had | undone |
| he/she/it | had | undone |
| we | had | undone |
| you | had | undone |
| they | had | undone |
单语范例（未经PONS编辑处理）
In the 19th century these alterations were to some extent undone.
en.wikipedia.org Any fastened nails must be undone, and no one should be punching nails to avoid stalled birth.
en.wikipedia.org With deep and highly customisable settings, countdown clocks, and a self-imposed lock-out feature that's very time-consuming to undo, you'll never dilly-dally online while you should be working again.
www.itproportal.com In this case more sophisticated techniques that involve multiple undo levels are used.
en.wikipedia.org However, the cloth was taken out about every two hours to undo plaits and wrinkles.
en.wikipedia.org