| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [been] unable [to-vb] | 516 |
|
| 2 | [been] unable [verb] | 516 |
|
| 3 | [been] [adj] to establish | 37 |
|
| 4 | [be] unable to establish | 12 |
|
| 5 | [been] unable establish | 9 |
|
