| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] over a period [prep] time | 75 |
|
| 2 | [noun] over a period of time | 75 |
|
| 3 | [noun sg] over a period [prep] time | 48 |
|
| 4 | [noun pl] over a period [prep] time | 23 |
|
