| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be difficult [prep] them [to-vb] | 27 |
|
| 2 | it difficult [prep] them [to-vb] | 20 |
|
| 3 | it be difficult [prep] them | 17 |
|
| 4 | it be [prep] them [to-vb] | 12 |
|
