| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | is required [prep] | 702 |
|
| 2 | [is] required for | 235 |
|
| 3 | [is] required in | 114 |
|
| 4 | [is] required by | 106 |
|
| 5 | [is] required to | 60 |
|
| 6 | [is] required of | 54 |
|
| 7 | [is] required at | 21 |
|
| 8 | [is] required on | 21 |
|
| 9 | [is] required from | 20 |
|
| 10 | [is] required under | 10 |
|
| 11 | [is] required before | 10 |
|
| 12 | [is] required between | 9 |
|
| 13 | [is] required with | 9 |
|
| 14 | [is] required as | 7 |
|
| 15 | [is] required during | 7 |
|
| 16 | [is] required over | 5 |
|
