| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which [vb -s] back to the [adj] | 17 |
|
| 2 | which dates back [prep] the [adj] | 11 |
|
| 3 | which [vb -s] back [prep] the [num ord] | 9 |
|
| 4 | which [vb -s] back [prep] the [adj] | 7 |
|
