| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at [det] a | 336 |
|
| 2 | at such a | 319 |
|
| 3 | at [det] an | 69 |
|
| 4 | at most a | 36 |
|
| 5 | at all a | 27 |
|
| 6 | at half a | 9 |
|
| 7 | at such-and-such a | 5 |
|
