| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a time when [adj] [noun sg] | 68 |
|
| 2 | at a time [Wh adv] [adj] [noun sg] | 68 |
|
| 3 | [prep] a time [Wh adv] [adj] [noun sg] | 56 |
|
| 4 | [prep] a time [Wh adv] [det] [noun sg] | 11 |
|
