| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period [verb] | 22 |
|
| 2 | over a [adj] period [v-ing] | 8 |
|
| 3 | over a [adj] period [to-vb] | 5 |
|
| 4 | over a [adj] period [vb -s] | 5 |
|
| 5 | over a long period [verb] | 5 |
|
