| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] it [is] difficult [verb] | 75 |
|
| 2 | [adv] because it [is] [verb] | 67 |
|
| 3 | because it [is] difficult [verb] | 18 |
|
| 4 | [adv] because it [is] difficult | 7 |
|
