| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] it is difficult [verb] | 65 |
|
| 2 | [adv] because it is [verb] | 58 |
|
| 3 | because it is difficult [verb] | 17 |
|
| 4 | [adv] because it is difficult | 8 |
|
