| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] once in [art] | 25 |
|
| 2 | at once in [art] | 17 |
|
| 3 | at once in [art] | 17 |
|
| 4 | [prep] once in a | 12 |
|
| 5 | [prep] once in the | 11 |
|
| 6 | for once in [art] | 5 |
|
| 7 | for once in [art] | 5 |
|
