| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period [prep] | 773 |
|
| 2 | [det] [prep] a [adj] [prep] | 16 |
|
| 3 | [det] [prep] a [adj] period | 12 |
|
| 4 | [det] a [adj] period [prep] | 12 |
|
| 5 | [det] [prep] a period [prep] | 12 |
|
