| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] used to | 2564 |
|
| 2 | what [modal v] to | 187 |
|
| 3 | what [vb mod] to | 187 |
|
| 4 | what used to | 139 |
|
| 5 | what used [prep] | 139 |
|
