| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [Wh pn] [verb] n't [been] able | 5 |
|
| 2 | who [verb] n't [been] able | 5 |
|
| 3 | [Wh pn] have n't [been] able | 5 |
|
| 4 | [Wh pn] [verb] n't been able | 5 |
|
