| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | do n't know [prep] sure | 25 |
|
| 2 | [verb] n't know for sure | 25 |
|
| 3 | [vb base] n't know [prep] sure | 22 |
|
| 4 | do n't know [prep] sure | 22 |
|
