| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a prolonged period [prep] | 20 |
|
| 2 | [prep] a prolonged period [prep] | 20 |
|
| 3 | over a prolonged period [prep] | 9 |
|
| 4 | over a prolonged period [prep] | 9 |
|
| 5 | [verb] a prolonged period [prep] | 5 |
|
| 6 | a prolonged period [prep] [noun] | 19 |
|
| 7 | a prolonged period [prep] [noun sg] | 18 |
|
| 8 | a prolonged period [prep] time | 11 |
|
| 9 | a prolonged period [prep] time | 11 |
|
| 10 | a prolonged period [prep] [adj] | 9 |
|
| 11 | a prolonged period [prep] [adj] | 9 |
|
