| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult [to-vb] [adj] [noun pl] | 214 |
|
| 2 | it difficult [to-vb] [adj] | 118 |
|
| 3 | it [to-vb] [adj] [noun pl] | 84 |
|
| 4 | it difficult [to-vb] [noun pl] | 56 |
|
