| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult it is [to-vb] [art] | 16 |
|
| 2 | difficult it is [verb] [art] | 16 |
|
| 3 | difficult it is [verb] a | 10 |
|
| 4 | difficult it is [verb] the | 6 |
|
