| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is very difficult | 359 |
|
| 2 | is more difficult | 216 |
|
| 3 | is extremely difficult | 142 |
|
| 4 | is often difficult | 105 |
|
| 5 | is notoriously difficult | 41 |
|
| 6 | is so difficult | 39 |
|
| 7 | is quite difficult | 37 |
|
| 8 | is always difficult | 35 |
|
| 9 | is sometimes difficult | 34 |
|
| 10 | is too difficult | 32 |
|
| 11 | is particularly difficult | 28 |
|
| 12 | is also difficult | 25 |
|
| 13 | is rather difficult | 19 |
|
| 14 | is increasingly difficult | 19 |
|
| 15 | is still difficult | 17 |
|
| 16 | is therefore difficult | 15 |
|
| 17 | is especially difficult | 14 |
|
| 18 | is usually difficult | 14 |
|
| 19 | is obviously difficult | 7 |
|
| 20 | is most difficult | 7 |
|
| 21 | is surprisingly difficult | 7 |
|
| 22 | is less difficult | 7 |
|
| 23 | is as difficult | 7 |
|
| 24 | is extraordinarily difficult | 6 |
|
| 25 | is thus difficult | 6 |
|
| 26 | is now difficult | 6 |
|
| 27 | is equally difficult | 6 |
|
| 28 | is exceedingly difficult | 6 |
|
| 29 | is frequently difficult | 6 |
|
| 30 | is both difficult | 5 |
|
