| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it is [prep] [be] [adj] | 62 |
|
| 2 | it is difficult [prep] [be] | 40 |
|
| 3 | is difficult [prep] [be] [adj] | 34 |
|
| 4 | it is difficult [prep] [adj] | 13 |
|
| 5 | it difficult [prep] [be] [adj] | 7 |
|
