| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] [vb pp] at a | 236 |
|
| 2 | [adv] at a time | 151 |
|
| 3 | [vb pp] at a time | 148 |
|
| 4 | [adv] [vb pp] a time | 8 |
|
