| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [was/were] [vb pp] at a | 613 |
|
| 2 | [vb pp] at a time | 148 |
|
| 3 | [was/were] at a time | 21 |
|
| 4 | [was/were] [vb pp] at time | 7 |
|
