| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | occur at a time | 18 |
|
| 2 | occur at the time | 13 |
|
| 3 | occurred at [art] time | 13 |
|
| 4 | occurs at [art] time | 7 |
|
| 5 | occurring at [art] time | 6 |
|
