| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] at a [noun] | 1213 |
|
| 2 | [adv] at a [noun sg] | 1161 |
|
| 3 | [adv] at [art] time | 643 |
|
| 4 | [adv] [prep] a time | 464 |
|
| 5 | [adv] at a time | 151 |
|
