| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is [adv] difficult think | 10 |
|
| 2 | it is [adv] difficult think | 6 |
|
| 3 | it is difficult think [prep] | 18 |
|
| 4 | it is difficult think [prep] | 18 |
|
| 5 | it is difficult think of | 16 |
|
| 6 | it is difficult think of | 16 |
|
