| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period [prep] | 773 |
|
| 2 | [prep] a [adv] [adj] period | 175 |
|
| 3 | a [adv] [adj] period [prep] | 121 |
|
| 4 | [prep] a [adv] [adj] [prep] | 29 |
|
