| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] once [prep] a | 41 |
|
| 2 | [noun sg] once [prep] a | 29 |
|
| 3 | [noun] once in a | 22 |
|
| 4 | [noun pl] once [prep] a | 11 |
|
| 5 | [noun] once upon a | 9 |
|
