| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun sg] once [prep] a [noun] | 26 |
|
| 2 | [noun sg] once [prep] a [noun sg] | 26 |
|
| 3 | [noun sg] once [prep] a [noun] | 23 |
|
| 4 | [noun sg] once in a [noun] | 13 |
|
| 5 | [noun sg] once in a [noun] | 13 |
|
| 6 | [noun sg] once [prep] a while | 10 |
|
| 7 | [noun sg] once [prep] a while | 10 |
|
