| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [art] [noun sg] once in a | 8 |
|
| 2 | [art] [noun sg] once in a | 8 |
|
| 3 | [noun sg] once in a [noun sg] | 13 |
|
| 4 | [noun sg] once in a [noun] | 13 |
|
| 5 | [noun sg] once in a while | 10 |
|
| 6 | [noun sg] once in a while | 10 |
|
