| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it has proved [adj] | 40 |
|
| 2 | it has proved impossible | 9 |
|
| 3 | it has proved impossible | 9 |
|
| 4 | it has proved possible | 7 |
|
| 5 | it has proved possible | 7 |
|
| 6 | it has proved difficult | 6 |
|
| 7 | it has proved difficult | 6 |
|
