| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] difficult [prep] be sure | 18 |
|
| 2 | be difficult [prep] [be] sure | 18 |
|
| 3 | [be] difficult to [be] sure | 18 |
|
| 4 | [be] difficult [prep] [be] sure | 18 |
|
| 5 | [be] difficult [prep] be sure | 18 |
|
| 6 | [is] difficult [prep] [be] sure | 13 |
|
| 7 | is difficult [prep] [be] sure | 9 |
|
| 8 | was difficult [prep] [be] sure | 5 |
|
| 9 | [was/were] difficult [prep] [be] sure | 5 |
|
