| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a period [prep] | 2665 |
|
| 2 | a [adj -er] period | 230 |
|
| 3 | [adj -er] period [prep] | 107 |
|
| 4 | a [adj -er] [prep] | 83 |
|
