| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] [adj -er] period of | 10 |
|
| 2 | much [adj -er] period of | 7 |
|
| 3 | much [adj -er] period of | 7 |
|
| 4 | [adv] longer period of | 5 |
|
