| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [noun] at a [noun] | 727 |
|
| 2 | a [noun] at a [noun sg] | 644 |
|
| 3 | a [noun] at [art] time | 237 |
|
| 4 | [art] [noun] at a time | 191 |
|
| 5 | a [noun] [prep] a time | 171 |
|
| 6 | a [noun] at a time | 118 |
|
