| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun pl] [prep] a [adj] period | 229 |
|
| 2 | [noun pl] [prep] a long [noun] | 208 |
|
| 3 | [noun] [prep] a long period | 177 |
|
| 4 | [noun pl] [prep] [art] long period | 43 |
|
| 5 | [noun pl] [prep] a long period | 42 |
|
