| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] year | 891 |
|
| 2 | [prep] a [num] year | 491 |
|
| 3 | [prep] a fifteen [noun] | 21 |
|
| 4 | [prep] a fifteen [noun sg] | 19 |
|
| 5 | [prep] [art] fifteen year | 12 |
|
| 6 | [prep] [art] fifteen year | 12 |
|
| 7 | [prep] a fifteen year | 10 |
|
| 8 | [prep] a fifteen year | 9 |
|
| 9 | [prep] a fifteen year | 9 |
|
| 10 | [prep] a fifteen year | 9 |
|
