| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | could have happened at [adj] time | 5 |
|
| 2 | could have happened at any [noun sg] | 5 |
|
| 3 | could have happened at [adj] [noun sg] | 5 |
|
| 4 | could have happened at any [noun sg] | 5 |
|
| 5 | could have happened at [det] [noun sg] | 5 |
|
