| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a four [noun] period [prep] | 6 |
|
| 2 | [prep] a four [noun] period [prep] | 6 |
|
| 3 | over a four [noun] period [prep] | 5 |
|
| 4 | over a four [noun] period [prep] | 5 |
|
