| Clue | Source | Date |
|---|---|---|
| Zero times | ||
| At no time | Newsday | 03 Dec 2018 |
| 'When pigs fly!' | The Washington Post | 13 Apr 2016 |
| When pigs fly | ||
| At no time | ||
| At no time | ||
| At no time | ||
| At no time | ||
| When donkeys fly? | ||
| "When pigs fly!" | ||
| "Ain't gonna happen" | ||
| "When pigs fly!" | ||
| When hell freezes over | ||
| When donkeys fly? | ||
| At no time. |