| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [adv] difficult [verb] | 994 |
|
| 2 | is [adv] difficult [to-vb] | 989 |
|
| 3 | is [adv] [adj] to achieve | 65 |
|
| 4 | [be] [adv] difficult to achieve | 37 |
|
| 5 | be [adv] difficult to achieve | 37 |
|
| 6 | is [adv] difficult achieve | 20 |
|
| 7 | [is] [adv] difficult to achieve | 20 |
|
