| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb mod] be [verb] back [prep] a | 17 |
|
| 2 | [vb mod] be [vb pp] back [prep] a | 16 |
|
| 3 | [vb mod] be [verb] back to a | 10 |
|
| 4 | can be [verb] back [prep] a | 10 |
|
| 5 | [vb mod] be traced back [prep] a | 7 |
|
| 6 | [vb mod] be trace back [prep] a | 7 |
|
