One of my duties

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. One of my duties is attend meetings.
  2. One of my duties is to attend meetings.
  3. One of my duties is attending meetings.
    Please correct the above.
    The only thing he likes to do is (sing)/(to sing)/(singing).
    Is this also correct?
    Thanks.
2

1 is not correct.

‘singing’ is not strictly correct and should be avoided in favour of one of the other options.