| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a long period of time | 11 |
|
| 2 | [adv] a long period [prep] time | 11 |
|
| 3 | [adv] a long period [prep] time | 11 |
|
| 4 | [adv] a long period [prep] time | 11 |
|
| 5 | [adv prt] a long period [prep] time | 8 |
|
| 6 | over a long period [prep] time | 8 |
|
| 7 | over a long period [prep] time | 8 |
|
