| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [adj] years ' duration | 71 |
|
| 2 | four years ' [noun] | 68 |
|
| 3 | four [noun] ' duration | 28 |
|
| 4 | four [noun pl] ' duration | 28 |
|
| 5 | four years [unc] duration | 27 |
|
| 6 | four years ['s] duration | 27 |
|
| 7 | four year ' duration | 27 |
|
| 8 | four years ' duration | 27 |
|
