| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | although it is [adv] difficult | 6 |
|
| 2 | although it is [adv] difficult | 6 |
|
| 3 | although it is difficult [to-vb] | 30 |
|
| 4 | although it is difficult [verb] | 30 |
|
