| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is [adv] difficult [to-vb] | 825 |
|
| 2 | is very difficult [verb] | 229 |
|
| 3 | is more difficult [verb] | 114 |
|
| 4 | is extremely difficult [verb] | 91 |
|
| 5 | is often difficult [verb] | 80 |
|
| 6 | is [adv] difficult find | 29 |
|
| 7 | is [adv] difficult to find | 29 |
|
| 8 | is [adv] difficult to make | 28 |
|
| 9 | is [adv] difficult make | 28 |
|
| 10 | is notoriously difficult [verb] | 27 |
|
| 11 | is sometimes difficult [verb] | 26 |
|
| 12 | is [adv] difficult to assess | 25 |
|
| 13 | is [adv] difficult assess | 25 |
|
| 14 | is always difficult [verb] | 23 |
|
| 15 | is [adv] difficult to see | 22 |
|
| 16 | is [adv] difficult see | 22 |
|
| 17 | is [adv] difficult establish | 21 |
|
| 18 | is [adv] difficult to determine | 21 |
|
| 19 | is [adv] difficult get | 21 |
|
| 20 | is [adv] difficult determine | 21 |
|
| 21 | is [adv] difficult to establish | 21 |
|
| 22 | is so difficult [verb] | 20 |
|
| 23 | is quite difficult [verb] | 20 |
|
| 24 | is also difficult [verb] | 20 |
|
| 25 | is [adv] difficult to get | 20 |
|
| 26 | is [adv] difficult predict | 20 |
|
| 27 | is [adv] difficult to predict | 20 |
|
| 28 | is [adv] difficult achieve | 19 |
|
| 29 | is [adv] difficult to achieve | 19 |
|
| 30 | is [adv] difficult to do | 16 |
|
