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