| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb -s] back to the [adj] century | 40 |
|
| 2 | [vb -s] back [prep] the [num ord] century | 40 |
|
| 3 | [vb -s] back [prep] the [adj] century | 40 |
|
| 4 | [vb -s] back [prep] the [adj] century | 39 |
|
| 5 | dates back [prep] the [adj] century | 27 |
|
| 6 | goes back [prep] the [adj] century | 13 |
|
| 7 | [vb -s] back [prep] the 13th century | 5 |
|
| 8 | [vb -s] back [prep] the 13th century | 5 |
|
