| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at [adv] [num] a [noun] | 13 |
|
| 2 | [prep] [adv] [num] a year | 13 |
|
| 3 | at [adv] [adj] a year | 7 |
|
| 4 | at [adv] [num] a year | 6 |
|
| 5 | at [adv] [num] [art] year | 6 |
|
