| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun pl] [prep] an [adj] period | 20 |
|
| 2 | [noun pl] [prep] an earlier period | 9 |
|
| 3 | [noun pl] [prep] an [adj -er] period | 9 |
|
| 4 | [noun pl] [prep] an early period | 9 |
|
| 5 | [noun pl] of an [adj] period | 8 |
|
| 6 | [noun pl] over an [adj] period | 7 |
|
| 7 | [noun pl] for an [adj] period | 6 |
|
