| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a period of [noun] | 575 |
|
| 2 | [prep] a period of [noun sg] | 452 |
|
| 3 | over a period of [noun] | 296 |
|
| 4 | over a period of [noun] | 296 |
|
| 5 | [prep] a period of time | 239 |
|
| 6 | [prep] a period of time | 239 |
|
| 7 | [prep] a period of [noun pl] | 123 |
|
| 8 | [prep] a period of year | 71 |
|
| 9 | [prep] a period of years | 70 |
|
| 10 | for a period of [noun] | 59 |
|
| 11 | for a period of [noun] | 59 |
|
| 12 | after a period of [noun] | 57 |
|
| 13 | after a period of [noun] | 57 |
|
| 14 | in a period of [noun] | 38 |
|
| 15 | in a period of [noun] | 38 |
|
| 16 | [prep] a period of month | 20 |
|
| 17 | [prep] a period of months | 20 |
|
| 18 | [prep] a period of weeks | 19 |
|
| 19 | during a period of [noun] | 19 |
|
| 20 | during a period of [noun] | 19 |
|
| 21 | [prep] a period of week | 19 |
|
| 22 | to a period of [noun] | 16 |
|
| 23 | to a period of [noun] | 16 |
|
| 24 | of a period of [noun] | 16 |
|
| 25 | of a period of [noun] | 16 |
|
| 26 | as a period of [noun] | 16 |
|
| 27 | as a period of [noun] | 16 |
|
| 28 | by a period of [noun] | 15 |
|
| 29 | by a period of [noun] | 15 |
|
| 30 | through a period of [noun] | 12 |
|
