| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period | 1796 |
|
| 2 | [prep] such a [adj] | 1792 |
|
| 3 | such a [adj] period | 32 |
|
| 4 | [prep] such a period | 18 |
|
