| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [pron] could not be sure | 75 |
|
| 2 | he could not be [adj] | 55 |
|
| 3 | he could [adv] be sure | 26 |
|
| 4 | he [modal v] not be sure | 24 |
|
| 5 | he could not [be] sure | 23 |
|
