| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [be] trace back [prep] the | 5 |
|
| 2 | [verb] [be] traced back [prep] the | 5 |
|
| 3 | [verb] be trace back [prep] the | 5 |
|
| 4 | [verb] [been] trace back [prep] the | 5 |
|
| 5 | [verb] been trace back [prep] the | 5 |
|
| 6 | have [be] trace back [prep] the | 5 |
|
| 7 | [verb] [be] trace back to the | 5 |
|
