| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a period [prep] | 41 |
|
| 2 | [adv] a period [prep] | 41 |
|
| 3 | [adv] a period of | 37 |
|
| 4 | [adv] a period of | 37 |
|
| 5 | long a period [prep] | 7 |
|
| 6 | also a period [prep] | 6 |
|
