| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | be his duty [to-vb] | 28 |
|
| 2 | be his duty [verb] | 28 |
|
| 3 | be his duty [prep] | 6 |
|
| 4 | be his duty [prep] | 6 |
|
| 5 | [pron] be his duty | 36 |
|
| 6 | it be his duty | 36 |
|
| 7 | [pers pn] be his duty | 36 |
|
| 8 | it be his duty | 36 |
|
| 9 | be his [adj] duty | 10 |
|
| 10 | be his [adj] duty | 9 |
|
