| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | had been able [verb] a | 21 |
|
| 2 | had be able [verb] a | 21 |
|
| 3 | had [been] able [verb] a | 21 |
|
| 4 | had [be] able [to-vb] a | 21 |
|
