| Idiom | % Correct |
|---|---|
| Not in a million {years} | 96%
|
| When {hell} freezes over | 95%
|
| Don't hold your {breath} | 94%
|
| When {pigs} fly | 92%
|
| Once in a blue {moon} | 86%
|
| When the {sun} rises in the west | 85%
|
| In your {dreams} | 84%
|
| Few and {far} between | 80%
|
| Beating a {dead} horse | 69%
|
| Between a rock and a {hard} {place} | 61%
|
| Close but no {cigar} | 61%
|
| That is out of the {question} | 61%
|
| On the 30th of {February} | 56%
|
| Like getting {blood} from a stone | 49%
|
| Twelfth of {never} | 39%
|
| A {snowball's} chance in hell | 34%
|