| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at [adv] [prep] a | 274 |
|
| 2 | at [adv] [prep] a | 271 |
|
| 3 | at once [prep] [art] | 139 |
|
| 4 | [prep] once [prep] a | 63 |
|
| 5 | [prep] once [prep] a | 63 |
|
| 6 | at once [prep] a | 50 |
|
| 7 | at once [prep] a | 50 |
|
| 8 | at once [prep] a | 50 |
|
