| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is difficult [to-vb] the | 239 |
|
| 2 | is difficult [to-vb] the [noun sg] | 156 |
|
| 3 | it is [to-vb] the [noun sg] | 92 |
|
| 4 | it difficult [to-vb] the [noun sg] | 83 |
|
| 5 | it is difficult [to-vb] [noun sg] | 53 |
|
