| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | have [been] used for many [noun pl] | 13 |
|
| 2 | have been used for many [noun pl] | 13 |
|
| 3 | have [been] used for many years | 11 |
|
| 4 | has [been] used for many [noun pl] | 8 |
|
