| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [adj] period [prep] | 1333 |
|
| 2 | for a [adj] period | 756 |
|
| 3 | for a period [prep] | 389 |
|
| 4 | for a [adj] [prep] | 124 |
|
| 5 | for [adj] period [prep] | 40 |
|
