| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it was difficult for [pron] [to-vb] | 18 |
|
| 2 | it was difficult for [pers pn] [to-vb] | 17 |
|
| 3 | it was difficult for him [to-vb] | 6 |
|
| 4 | it was difficult for he [to-vb] | 6 |
|
