| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | what [verb] when | 440 |
|
| 2 | what happen when | 366 |
|
| 3 | what happened [conj] | 181 |
|
| 4 | what happened [subord] | 131 |
|
| 5 | [pron] happened when | 102 |
|
| 6 | what [vb past] when | 84 |
|
| 7 | [Wh det] happened when | 84 |
|
| 8 | what happened when | 81 |
|
| 9 | what happened when | 81 |
|
