| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | at a [noun] | 15341 |
|
| 2 | at a [noun sg] | 14548 |
|
| 3 | at [art] cost | 799 |
|
| 4 | at [art] cost | 799 |
|
| 5 | [prep] a cost | 593 |
|
| 6 | at a cost | 517 |
|
| 7 | at a cost | 517 |
|
