| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [art] [num] year [noun sg] period | 13 |
|
| 2 | [art] [num] year [noun sg] period | 13 |
|
| 3 | a [num] year [noun sg] period | 10 |
|
| 4 | a [num] year [noun sg] period | 10 |
|
