| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] on a | 4263 |
|
| 2 | once [prep] a | 498 |
|
| 3 | once [prep] a | 498 |
|
| 4 | once on [art] | 89 |
|
| 5 | once on a | 19 |
|
