| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | understand what have happen | 10 |
|
| 2 | understand [Wh det] have happen | 10 |
|
| 3 | understand [pron] have happened | 10 |
|
| 4 | understand what have happen | 10 |
|
| 5 | understand [pron] had happen | 5 |
|
