| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a long period | 391 |
|
| 2 | [prep] a long [conj] | 131 |
|
| 3 | [prep] a period [conj] | 49 |
|
| 4 | a long period [conj] | 35 |
|
