| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at [art] time [Wh adv] a | 21 |
|
| 2 | at [art] time when a | 21 |
|
| 3 | at a time [Wh adv] a | 19 |
|
| 4 | at a time [Wh adv] a | 19 |
|
