| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] four years | 820 |
|
| 2 | for four years | 341 |
|
| 3 | to four years | 118 |
|
| 4 | in four years | 106 |
|
| 5 | of four years | 83 |
|
| 6 | after four years | 80 |
|
| 7 | within four years | 28 |
|
| 8 | by four years | 9 |
|
| 9 | over four years | 8 |
|
| 10 | from four years | 8 |
|
| 11 | at four years | 7 |
|
| 12 | with four years | 5 |
|
