| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a | 121522 |
|
| 2 | [adv] a | 77420 |
|
| 3 | once [art] | 2973 |
|
| 4 | once [art] | 2973 |
|
| 5 | once a | 1996 |
|
| 6 | once a | 1878 |
|
