| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] once [prep] a [noun sg] | 8 |
|
| 2 | [adj] once [prep] a [noun] | 8 |
|
| 3 | [adj] once [prep] a while | 6 |
|
| 4 | [adj] once in a [noun] | 6 |
|
| 5 | [adj] once [prep] a while | 6 |
|
