| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [adv] a period of | 67 |
|
| 2 | [vb past] [adv] a period of | 23 |
|
| 3 | [be] [adv] a period of | 17 |
|
| 4 | be [adv] a period of | 17 |
|
| 5 | [adv] [adv] a period of | 13 |
|
| 6 | [v-ing] [adv] a period of | 12 |
|
| 7 | [adv] [adv] a period of | 12 |
|
| 8 | [was/were] [adv] a period of | 10 |
|
| 9 | [vb -s] [adv] a period of | 9 |
|
| 10 | was [adv] a period of | 7 |
|
| 11 | is [adv] a period of | 7 |
|
| 12 | [is] [adv] a period of | 7 |
|
| 13 | [vb pp] [adv] a period of | 6 |
|
| 14 | [vb base] [adv] a period of | 6 |
|
| 15 | [to-vb] [adv] a period of | 6 |
|
| 16 | occur [adv] a period of | 5 |
|
| 17 | [conj] [adv] a period of | 5 |
|
| 18 | extend [adv] a period of | 5 |
|
| 19 | [vb infin] [adv] a period of | 5 |
|
| 20 | [adv] [prep] a period of | 129 |
|
| 21 | [adv] [prep] a period of | 129 |
|
| 22 | [adv] over a period of | 60 |
|
| 23 | [adv] over a period of | 60 |
|
| 24 | [adv] [verb] a period of | 24 |
|
| 25 | [adv] for a period of | 23 |
|
| 26 | [adv] for a period of | 23 |
|
| 27 | [adv] after a period of | 16 |
|
| 28 | [adv] after a period of | 16 |
|
| 29 | [adv] [adv] a period of | 13 |
|
| 30 | [adv] [adv] a period of | 11 |
|
