| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which date back [prep] the [num ord] | 11 |
|
| 2 | which date back [prep] the [num ord] | 11 |
|
| 3 | which date back to the [num ord] | 11 |
|
| 4 | which date back to the [num ord] | 11 |
|
| 5 | which date back [prep] the [num ord] | 11 |
|
| 6 | which dates back [prep] the [num ord] | 8 |
|
