| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a long period [prep] [noun sg] | 172 |
|
| 2 | for long period [prep] [noun sg] | 66 |
|
| 3 | for a period [prep] [noun sg] | 59 |
|
| 4 | for a long period [prep] | 33 |
|
