| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] year | 891 |
|
| 2 | [prep] a [num] year | 491 |
|
| 3 | [prep] a 30 [noun] | 29 |
|
| 4 | [prep] a 30 [noun sg] | 16 |
|
| 5 | [prep] [art] 30 year | 9 |
|
| 6 | [prep] [art] 30 year | 9 |
|
| 7 | [prep] a 30 year | 8 |
|
| 8 | [prep] a 30 year | 8 |
|
| 9 | [prep] a 30 year | 8 |
|
| 10 | [prep] a 30 year | 8 |
|
