| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] year | 1787 |
|
| 2 | period [prep] [adj] year | 378 |
|
| 3 | period [prep] a [adj] | 95 |
|
| 4 | period [prep] a year | 15 |
|
