| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a [noun sg] or [adv] a | 13 |
|
| 2 | once [art] [noun sg] or [adv] a | 7 |
|
| 3 | [adv] [art] [noun sg] or once a | 6 |
|
