| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] over a prolonged period | 12 |
|
| 2 | [noun sg] over a prolonged period | 6 |
|
| 3 | over a prolonged period [prep] | 9 |
|
| 4 | over a prolonged period [prep] | 9 |
|
| 5 | over a prolonged period of | 8 |
|
| 6 | over a prolonged period of | 8 |
|
