| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [noun] [prep] a [adj] period | 766 |
|
| 2 | [noun] [prep] a period of | 652 |
|
| 3 | [prep] a [adj] period of | 544 |
|
| 4 | [noun] [prep] a [adj] of | 135 |
|
| 5 | [noun] [prep] [adj] period of | 77 |
|
| 6 | [noun] a [adj] period of | 7 |
|
