| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which [vb mod] happen to | 10 |
|
| 2 | which [modal v] happen to | 10 |
|
| 3 | which [modal v] happen to | 10 |
|
| 4 | which may happen to | 5 |
|
| 5 | which may happen to | 5 |
|
