| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | a three [noun] period [prep] | 8 |
|
| 2 | a three [noun] period [prep] | 8 |
|
| 3 | a three [noun sg] period [prep] | 8 |
|
| 4 | a three year period [prep] | 5 |
|
| 5 | a three year period [prep] | 5 |
|
