| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | once [prep] a [noun] [prep] [art] | 9 |
|
| 2 | once [prep] a [noun] [prep] [art] | 9 |
|
| 3 | once [prep] a [noun] [art] [noun] | 12 |
|
| 4 | once [prep] a [noun] [art] [noun sg] | 10 |
|
