| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [adv] difficult [verb] | 830 |
|
| 2 | is [adv] difficult [to-vb] | 825 |
|
| 3 | is [adv] [adj] to achieve | 49 |
|
| 4 | be [adv] difficult to achieve | 36 |
|
| 5 | [be] [adv] difficult to achieve | 36 |
|
| 6 | is [adv] difficult to achieve | 20 |
|
| 7 | is [adv] difficult achieve | 19 |
|
| 8 | [is] [adv] difficult to achieve | 19 |
|
