| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] a [noun sg] | 32940 |
|
| 2 | once a [noun sg] | 1545 |
|
| 3 | once [vb pp] a | 130 |
|
| 4 | once [vb pp] [noun sg] | 73 |
|
