| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] three years [unc] [noun] | 92 |
|
| 2 | [prep] [adj] years [unc] duration | 56 |
|
| 3 | [prep] three [noun pl] [unc] duration | 28 |
|
| 4 | [prep] three [noun] [unc] duration | 28 |
|
| 5 | [prep] three year [unc] duration | 25 |
|
