| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a period of [noun] | 297 |
|
| 2 | [prep] a period of time | 240 |
|
| 3 | [prep] a period of time | 240 |
|
| 4 | over a [noun] of time | 191 |
|
| 5 | over a [noun sg] of time | 191 |
|
| 6 | over [art] period of time | 188 |
|
| 7 | over a period of time | 185 |
|
| 8 | over a period of time | 185 |
|
| 9 | over a period [prep] time | 185 |
|
