| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [adj] period [prep] [noun sg] | 570 |
|
| 2 | for a [adj] period [prep] | 257 |
|
| 3 | for a period [prep] [noun sg] | 59 |
|
| 4 | for a [adj] [prep] [noun sg] | 6 |
|
