| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be [adj] account for | 82 |
|
| 2 | be difficult [verb] for | 29 |
|
| 3 | be difficult account for | 10 |
|
| 4 | be difficult account [prep] | 10 |
|
| 5 | be difficult account [prep] | 10 |
|
| 6 | [be] difficult account for | 10 |
|
