| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | difficult to establish [conj] [art] | 7 |
|
| 2 | difficult to establish [conj] the | 6 |
|
| 3 | difficult to establish [conj] the | 6 |
|
| 4 | difficult to establish [subord] [art] | 5 |
|
