| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] four year ' duration | 19 |
|
| 2 | [prep] four year ' duration | 19 |
|
| 3 | of four year ' duration | 18 |
|
| 4 | of four year ' duration | 18 |
|
| 5 | [conj] four year ' duration | 8 |
|
| 6 | [coord] four year ' duration | 8 |
|
| 7 | or four year ' duration | 7 |
|
| 8 | or four year ' duration | 7 |
|
