| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a long period [prep] [noun sg] | 172 |
|
| 2 | a period [prep] [art] [noun sg] | 71 |
|
| 3 | a long period [prep] [art] | 16 |
|
| 4 | 6 |
|
