| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [be] a [noun] | 19886 |
|
| 2 | [be] a difficult [noun] | 331 |
|
| 3 | it [be] a difficult | 127 |
|
| 4 | it [be] difficult [noun] | 9 |
|
| 5 | it a difficult [noun] | 6 |
|
