| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] [num] years ' [noun] | 684 |
|
| 2 | [prep] [num] [noun pl] ' duration | 68 |
|
| 3 | [prep] [num] [noun] ' duration | 68 |
|
| 4 | [prep] [num] years [unc] duration | 56 |
|
| 5 | [prep] [num] year ' duration | 56 |
|
| 6 | [prep] [adj] years ' duration | 56 |
|
| 7 | [prep] [num] years ['s] duration | 56 |
|
| 8 | [prep] [num] years ' duration | 56 |
|
| 9 | [prep] [num] years ' duration | 56 |
|
