| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] be [verb] back [prep] a | 19 |
|
| 2 | [vb mod] [be] [vb pp] back [prep] a | 18 |
|
| 3 | [vb mod] [be] [verb] back [prep] a | 17 |
|
| 4 | can [be] [verb] back [prep] a | 10 |
|
| 5 | [vb mod] [be] [verb] back to a | 10 |
|
| 6 | [vb mod] [be] traced back [prep] a | 7 |
|
| 7 | [vb mod] [be] trace back [prep] a | 7 |
|
