| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adv] a [adj] period [prep] [noun] | 18 |
|
| 2 | [adv] a [adj] period [prep] [noun] | 17 |
|
| 3 | [adv] a [adj] period of [noun] | 16 |
|
| 4 | [adv] a [adj] period of [noun] | 16 |
|
| 5 | [adv] a [adj] period [prep] [noun sg] | 15 |
|
| 6 | [adv] a [adj] period [prep] time | 11 |
|
| 7 | [adv] a [adj] period [prep] time | 11 |
|
| 8 | only a [adj] period [prep] [noun] | 9 |
|
| 9 | [adv] a short period [prep] [noun] | 7 |
|
