| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | once [prep] a [noun sg] | 396 |
|
| 2 | once in a [noun] | 164 |
|
| 3 | once upon a [noun] | 163 |
|
| 4 | once [prep] a time | 160 |
|
| 5 | once [prep] a time | 160 |
|
| 6 | once [prep] a while | 104 |
|
| 7 | once [prep] a while | 104 |
|
| 8 | once [prep] a lifetime | 23 |
|
| 9 | once [prep] a lifetime | 23 |
|
| 10 | once on a [noun] | 15 |
|
| 11 | once as a [noun] | 14 |
|
| 12 | once by a [noun] | 8 |
|
| 13 | once with a [noun] | 8 |
|
| 14 | once to a [noun] | 5 |
|
| 15 | once at a [noun] | 5 |
|
