| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | it becomes [adj] | 537 |
|
| 2 | it becomes [adj] | 472 |
|
| 3 | it [verb] difficult | 89 |
|
| 4 | it [vb -s] difficult | 60 |
|
| 5 | it become difficult | 33 |
|
| 6 | [pron] becomes difficult | 26 |
|
| 7 | it becomes difficult | 26 |
|
