| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it was difficult [to-vb] | 371 |
|
| 2 | it difficult [to-vb] that | 41 |
|
| 3 | was difficult [to-vb] that | 31 |
|
| 4 | it was [to-vb] that | 20 |
|
