| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it difficult for [pron] [to-vb] | 65 |
|
| 2 | it is difficult for [pron] | 57 |
|
| 3 | it is for [pron] [to-vb] | 44 |
|
| 4 | is difficult for [pron] [to-vb] | 43 |
|
