| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | back [prep] a [noun] | 921 |
|
| 2 | back [prep] a [noun sg] | 884 |
|
| 3 | [adv] [prep] a time | 464 |
|
| 4 | back [prep] [art] time | 77 |
|
| 5 | back [prep] [art] time | 77 |
|
| 6 | back [prep] a time | 17 |
|
| 7 | back [prep] a time | 17 |
|
| 8 | back [prep] a time | 17 |
|
