21. We feel ______ our duty to make our country a better place.
A. it B. this C. that D. one
22. My first ______ of him was that he was a kind and thoughtful young man.
A. expression B. attention C. satisfaction D. impression
23. It’s very hot here. Why not _______ your coat?
A. have on B. take off C. put off D. put on
