| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | which [verb] [prep] | 19596 |
|
| 2 | which [vb past] [prep] | 8214 |
|
| 3 | [pron] happened [prep] | 1950 |
|
| 4 | [Wh det] happened [prep] | 1416 |
|
| 5 | which happen [prep] | 129 |
|
| 6 | which happened [prep] | 64 |
|
