I think ______ is necessary ______us to do something useful to protect the birds.

r superstar Ding Junhui owes his great success to many people, his father _______.

We feel _______ our duty to make our school a better place. [ ]

You have no idea how she finished the relay race with her foot ____ so much.

“Learning from Lei Feng Day” is only two weeks from now. We need to ________ a plan about it.