| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a [adj] period of [noun] | 579 |
|
| 2 | [prep] a period of [noun] | 575 |
|
| 3 | [prep] a [adj] period of | 544 |
|
| 4 | [prep] [adj] period of [noun] | 119 |
|
| 5 | [prep] a [adj] of [noun] | 48 |
|
| 6 | [prep] a [adj] period [noun] | 14 |
|
