| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] used to [be] | 1772 |
|
| 2 | it [vb mod] to [be] | 684 |
|
| 3 | it [modal v] to [be] | 684 |
|
| 4 | it used [prep] [be] | 501 |
|
| 5 | it used to [be] | 501 |
|
