| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [noun] | 490659 |
|
| 2 | [prep] a [noun pl] | 3305 |
|
| 3 | [prep] a week | 1699 |
|
| 4 | [prep] [art] weeks | 202 |
|
