| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [coord] [prep] a [noun] | 7795 |
|
| 2 | once [prep] a [noun] | 416 |
|
| 3 | [coord] once a [noun] | 53 |
|
| 4 | [coord] once [prep] [noun] | 21 |
|
| 5 | [coord] once [prep] a | 12 |
|
