| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period | 545 |
|
| 2 | over a [adj] period | 488 |
|
| 3 | [prep] a long period | 305 |
|
| 4 | [prep] a long period | 305 |
|
| 5 | over a long period | 232 |
|
| 6 | over a long [noun] | 205 |
|
| 7 | over [art] long period | 183 |
|
| 8 | over a long period | 181 |
|
