He feels ________his duty to help others.

1. A.
   that
2. B.
   this
3. C.
   those
4. D.
   it

He feels ________his duty to help others.

[　　]

He feels ________his duty to help others.

[　　]

He feels it his duty ____ others.

        A.to help         B.to be coming       C.help      D.helped

He's always ready to help others as he feels ______ so.

1. A.
   it his duty to do
2. B.
   his duty to do
3. C.
   his duty do
4. D.
   his duty doing