| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at a time [adv] | 1379 |
|
| 2 | at a time [Wh adv] | 1344 |
|
| 3 | at a time when | 1342 |
|
| 4 | at a time when | 1342 |
|
| 5 | at a time [adv] | 33 |
|
