| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a long period [prep] [noun] | 160 |
|
| 2 | a long period [prep] [noun sg] | 154 |
|
| 3 | a long period of [noun] | 151 |
|
| 4 | a long period [prep] time | 102 |
|
| 5 | a long period [prep] time | 102 |
|
| 6 | a long period [prep] [noun pl] | 5 |
|
