| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [coord] [prep] a period of | 32 |
|
| 2 | [coord] [prep] a period of | 32 |
|
| 3 | and [prep] a period of | 23 |
|
| 4 | [coord] over a period of | 18 |
|
| 5 | [coord] for a period of | 7 |
|
| 6 | [coord] after a period of | 6 |
|
| 7 | but [prep] a period of | 6 |
|
