| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] such a [adj] period | 26 |
|
| 2 | [prep] [det] a [adj] period | 26 |
|
| 3 | [prep] [det] a long period | 10 |
|
| 4 | [prep] [det] a long period | 10 |
|
| 5 | [prep] [det] a short period | 9 |
|
| 6 | [prep] [det] a short period | 9 |
|
| 7 | over [det] a [adj] period | 8 |
|
| 8 | for [det] a [adj] period | 5 |
|
