| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adj] period [prep] time | 297 |
|
| 2 | [prep] a [adj] period [prep] time | 282 |
|
| 3 | [prep] a long period [prep] [noun] | 122 |
|
| 4 | [prep] a long period [prep] [noun sg] | 117 |
|
| 5 | [prep] a long period [prep] time | 98 |
|
| 6 | [prep] [art] long period [prep] time | 91 |
|
| 7 | [prep] a long period [prep] time | 88 |
|
| 8 | [prep] a long period [prep] time | 88 |
|
| 9 | [prep] a long period [prep] time | 88 |
|
| 10 | [prep] a long [noun] [prep] time | 88 |
|
