| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb base] [adv] once [art] [noun sg] | 11 |
|
| 2 | [vb base] [adv] once a [noun sg] | 9 |
|
| 3 | [vb base] [adv] once a [noun sg] | 9 |
|
| 4 | [vb base] [adv] once [art] week | 6 |
|
| 5 | [vb base] only once [art] [noun sg] | 5 |
|
