| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] of [adj] years ' duration | 48 |
|
| 2 | [be] of [num] years ' duration | 48 |
|
| 3 | [be] [prep] four years ' duration | 18 |
|
| 4 | [be] [prep] four years ' duration | 18 |
|
| 5 | [be] of four [noun pl] ' duration | 17 |
|
| 6 | [be] of four years ' duration | 17 |
|
| 7 | [be] of four years [unc] duration | 17 |
|
| 8 | [be] of four years ' duration | 17 |
|
| 9 | [be] of four year ' duration | 17 |
|
| 10 | [be] of four [noun] ' duration | 17 |
|
| 11 | [be] of four years ' [noun] | 17 |
|
