| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] [prep] [num] years ' duration | 49 |
|
| 2 | [be] [prep] [adj] years ' duration | 49 |
|
| 3 | [be] [prep] three [noun pl] ' duration | 26 |
|
| 4 | [be] [prep] three [noun] ' duration | 26 |
|
| 5 | [be] [prep] three years ' [noun] | 25 |
|
| 6 | [be] [prep] three years [unc] duration | 24 |
|
| 7 | [be] [prep] three years ' duration | 24 |
|
| 8 | [be] [prep] three year ' duration | 24 |
|
| 9 | [be] [prep] three years ' duration | 24 |
|
