WHY DO PEOPLE USUALLY SING

21. - DE THI TIENG ANH LOP 6 NANG CAO 1 DE THI TIENG ANH LOP 6 NANG CAO
DE THI TIENG ANH LOP 6 NANG CAO 1 DE THI TIENG ANH LOP 6 NANG CAO
21. Why do people usually sing ? A. They like birds. B. They feel happy. C. They want to tell a story . D. They like studying music.