| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [to-vb] [is] | 1110 |
|
| 2 | difficult [noun] [to-vb] | 300 |
|
| 3 | difficult [noun] [is] | 61 |
|
| 4 | difficult [to-vb] [is] | 40 |
|
