| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [det] be once a [noun] | 12 |
|
| 2 | [det] [be] once a [noun] | 12 |
|
| 3 | [det] [noun] once a [noun] | 9 |
|
| 4 | [det] [was/were] once a [noun] | 8 |
|
| 5 | [det] [noun sg] once a [noun] | 8 |
|
| 6 | [det] was once a [noun] | 8 |
|
