| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at an [noun] | 1398 |
|
| 2 | at an [noun sg] | 1270 |
|
| 3 | [prep] an average | 422 |
|
| 4 | [prep] an average | 422 |
|
| 5 | at [art] average | 69 |
|
| 6 | at [art] average | 69 |
|
| 7 | at a average | 67 |
|
| 8 | at an average | 67 |
|
| 9 | at an average | 67 |
|
