| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] over a [adj] period [modal v] | 8 |
|
| 2 | [noun pl] over a [adj] period [modal v] | 5 |
|
| 3 | over a [adj] period [modal v] [vb infin] | 6 |
|
| 4 | over a [adj] period [modal v] [verb] | 6 |
|
