| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [to-vb] [prep] [det] [noun] | 6845 |
|
| 2 | difficult [to-vb] [prep] [noun] | 309 |
|
| 3 | difficult [to-vb] [det] [noun] | 195 |
|
| 4 | difficult [to-vb] [prep] [det] | 148 |
|
| 5 | difficult [prep] [det] [noun] | 87 |
|
