| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a certain [noun] [prep] | 2263 |
|
| 2 | a certain [noun sg] [prep] | 2256 |
|
| 3 | a [adj] period [prep] | 1182 |
|
| 4 | a [adj] period [prep] | 1112 |
|
| 5 | a certain period [prep] | 26 |
|
| 6 | [art] certain period [prep] | 26 |
|
| 7 | a certain period [prep] | 26 |
|
| 8 | [art] certain period [prep] | 26 |
|
| 9 | a certain period [prep] | 26 |
|
