| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] 1973 when [art] | 8 |
|
| 2 | [prep] 1973 when [art] | 8 |
|
| 3 | in 1973 when [art] | 5 |
|
| 4 | in 1973 when [art] | 5 |
|
| 5 | 1973 when [art] [noun] | 9 |
|
| 6 | 1973 when [art] [noun sg] | 7 |
|
