| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a long [noun] | 4136 |
|
| 2 | [prep] a long [noun sg] | 4081 |
|
| 3 | [prep] a [adj] period | 2001 |
|
| 4 | [prep] [art] long period | 413 |
|
| 5 | [prep] a long period | 391 |
|
