| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | happen [adv] [prep] a [noun sg] | 18 |
|
| 2 | happen [adv] [prep] a [noun sg] | 18 |
|
| 3 | happen [adv] in a [noun sg] | 8 |
|
| 4 | happen [adv] in a [noun sg] | 8 |
|
