| No | Pattern | Freq | Relations |
|---|---|---|---|
| 31 | [noun] [prep] a long period [prep] | 71 |
|
| 32 | [noun] [prep] a long period [prep] | 71 |
|
| 33 | [noun] [prep] a long period of | 62 |
|
| 34 | [noun] [prep] a long period of | 62 |
|
| 35 | [noun] [prep] a long period [verb] | 7 |
|
