| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be mainly because [prep] | 14 |
|
| 2 | be mainly because of | 13 |
|
| 3 | be mainly because of | 13 |
|
| 4 | is mainly because [prep] | 7 |
|
| 5 | was mainly because [prep] | 5 |
|
