| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | when [prep] a | 89 |
|
| 2 | when in a | 26 |
|
| 3 | when on a | 14 |
|
| 4 | when as a | 12 |
|
| 5 | when after a | 11 |
|
| 6 | when for a | 9 |
|
