| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [noun sg] [prep] a period [prep] | 25 |
|
| 2 | a [noun] [prep] a period of | 25 |
|
| 3 | a [noun] [prep] a period [prep] | 25 |
|
| 4 | a [noun] [prep] a period of | 25 |
|
| 5 | a [noun] for a period [prep] | 10 |
|
| 6 | a [noun] over a period [prep] | 8 |
|
