| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] difficult [verb] [coord] [vb infin] | 50 |
|
| 2 | is [adv] difficult [verb] [coord] | 32 |
|
| 3 | is [adv] [verb] [coord] [vb infin] | 20 |
|
| 4 | is difficult [verb] [coord] [vb infin] | 11 |
|
