| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | what [vb past] it | 247 |
|
| 2 | what did it | 136 |
|
| 3 | what made it | 53 |
|
| 4 | what caused it | 15 |
|
| 5 | what started it | 8 |
|
| 6 | what had it | 5 |
|
