| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] 1987 when [art] | 12 |
|
| 2 | [prep] 1987 when [art] | 12 |
|
| 3 | [prep] 1987 when the | 9 |
|
| 4 | [prep] 1987 when the | 9 |
|
| 5 | in 1987 when [art] | 8 |
|
