| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | what had [verb] [subord] | 28 |
|
| 2 | what had [vb pp] [subord] | 28 |
|
| 3 | what had happen [subord] | 20 |
|
| 4 | what had happened [subord] | 20 |
|
| 5 | what had [verb] since | 5 |
|
