| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] a long period | 72 |
|
| 2 | [vb pp] [prep] a long period | 67 |
|
| 3 | [verb] over a long period | 46 |
|
| 4 | [verb] for a long period | 29 |
|
| 5 | [verb] [prep] a longer period | 19 |
|
| 6 | [to-vb] [prep] a long period | 7 |
|
| 7 | developed [prep] a long period | 5 |
|
| 8 | [verb] after a long period | 5 |
|
| 9 | develop [prep] a long period | 5 |
|
| 10 | [v-ing] [prep] a long period | 5 |
|
