| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it [is] difficult to be [adj] | 40 |
|
| 2 | it is difficult to be [adj] | 33 |
|
| 3 | it [is] difficult to be sure | 12 |
|
| 4 | it [is] difficult to be certain | 10 |
|
| 5 | it 's difficult to be [adj] | 7 |
|
