| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | over a [adj] period of | 128 |
|
| 2 | over a long period of | 77 |
|
| 3 | over a prolonged period of | 8 |
|
| 4 | over a considerable period of | 7 |
|
| 5 | over a short period of | 7 |
|
| 6 | over a given period of | 5 |
|
