| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period [prep] | 773 |
|
| 2 | [noun sg] [prep] a [adj] period | 519 |
|
| 3 | [noun sg] [prep] a period [prep] | 461 |
|
| 4 | [noun sg] [prep] a [adj] [prep] | 290 |
|
| 5 | [noun sg] [prep] [adj] period [prep] | 99 |
|
| 6 | [noun sg] a [adj] period [prep] | 6 |
|
