| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [be] used for many years | 12 |
|
| 2 | be used for many years | 12 |
|
| 3 | been used for many years | 11 |
|
| 4 | [been] used for many years | 11 |
|
| 5 | used for many years [prep] | 10 |
|
| 6 | used for many years [prep] | 10 |
|
| 7 | used for many years in | 5 |
|
| 8 | used for many years in | 5 |
|
