| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [adv] a number of years | 13 |
|
| 2 | [prep] [adv] a number of years | 9 |
|
| 3 | [prep] [adv] a number of years | 9 |
|
| 4 | for [adv] a number of years | 8 |
|
| 5 | for [adv] a number of years | 8 |
|
| 6 | [v-ing] [adv] a number of years | 5 |
|
| 7 | [adv] [prep] a number of years | 38 |
|
| 8 | [adv] [prep] a number of years | 38 |
|
| 9 | [adv] for a number of years | 25 |
|
| 10 | [adv] for a number of years | 25 |
|
| 11 | [adv] over a number of years | 9 |
|
| 12 | [adv] over a number of years | 9 |
|
