| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a period [prep] [adj] | 777 |
|
| 2 | [prep] a long period [prep] | 162 |
|
| 3 | a long period [prep] [adj] | 28 |
|
| 4 | [prep] long period [prep] [adj] | 27 |
|
