| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] [conj] [adj] [is] | 322 |
|
| 2 | difficult [to-vb] [conj] [adj] | 142 |
|
| 3 | difficult [to-vb] [conj] [is] | 8 |
|
