| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun pl] [prep] a [adj] period | 200 |
|
| 2 | [noun pl] [prep] a long period | 42 |
|
| 3 | [noun] [prep] a longer period | 40 |
|
| 4 | [noun pl] [prep] a longer [noun] | 30 |
|
| 5 | [noun pl] [prep] a longer [noun sg] | 30 |
|
| 6 | [noun pl] [prep] a [adj -er] period | 16 |
|
| 7 | [noun pl] [prep] a longer period | 13 |
|
| 8 | [noun pl] [prep] a longer period | 13 |
|
| 9 | [noun pl] [prep] [art] longer period | 13 |
|
| 10 | [noun pl] [prep] [art] longer period | 13 |
|
