| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj -er] period [prep] | 36 |
|
| 2 | [prep] a [adj -er] period [prep] | 36 |
|
| 3 | [prep] a [adj -er] period of | 29 |
|
| 4 | [prep] a [adj -er] period of | 29 |
|
| 5 | [prep] a longer period [prep] | 17 |
|
| 6 | for a [adj -er] period [prep] | 15 |
|
| 7 | for a [adj -er] period [prep] | 15 |
|
| 8 | over a [adj -er] period [prep] | 10 |
|
| 9 | over a [adj -er] period [prep] | 10 |
|
| 10 | [prep] a further period [prep] | 9 |
|
| 11 | [prep] a shorter period [prep] | 6 |
|
