| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] to account for | 119 |
|
| 2 | difficult [verb] for | 77 |
|
| 3 | difficult [to-vb] for | 77 |
|
| 4 | difficult to account [prep] | 20 |
|
| 5 | difficult to account [prep] | 20 |
|
| 6 | difficult account for | 20 |
|
| 7 | difficult to account for | 20 |
|
