| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it difficult [to-vb] | 1117 |
|
| 2 | difficult [to-vb] [conj] | 1092 |
|
| 3 | it [to-vb] [conj] | 246 |
|
| 4 | it difficult [conj] | 33 |
|
