| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [num] year ['s] duration | 76 |
|
| 2 | [num] years ['s] duration | 70 |
|
| 3 | [num] year ' duration | 70 |
|
| 4 | four year ['s] duration | 28 |
|
| 5 | three year ['s] duration | 25 |
|
| 6 | two year ['s] duration | 7 |
|
| 7 | [num] year 's duration | 6 |
|
| 8 | [num] year ['s] duration | 6 |
|
| 9 | one year ['s] duration | 5 |
|
