| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [vb pp] [adv] [prep] a period | 13 |
|
| 2 | [verb] [adv] over a period | 12 |
|
| 3 | [verb] [adv] for a period | 11 |
|
| 4 | [vb past] [adv] [prep] a period | 6 |
|
| 5 | [to-vb] [adv] [prep] a period | 6 |
|
| 6 | [vb infin] [adv] [prep] a period | 5 |
|
| 7 | [vb -s] [adv] [prep] a period | 5 |
|
