| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult [to-vb] [is] [not/n't] it | 10 |
|
| 2 | difficult [to-vb] [is] [not/n't] [pers pn] | 10 |
|
| 3 | difficult [to-vb] [is] [not/n't] [pron] | 10 |
|
| 4 | difficult [to-vb] [is] [not/n't] it | 10 |
|
