| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb past] [prep] a [noun sg] | 18393 |
|
| 2 | once [prep] a [noun sg] | 411 |
|
| 3 | once [vb past] a [noun sg] | 163 |
|
| 4 | once [vb past] [prep] a | 67 |
|
| 5 | once [vb past] [prep] [noun sg] | 28 |
|
