Đáp án tham khảo có thể sai: 1a, 2d, 3a, 4b, 5c, 6a, 7d, 8c, 9d, 10a, 11b, 12d, 13b, 14a, 15a, 16c, 17a, 18c, 19b, 20d, 21d, 22c, 23b, 24a, 25b, 26b, 27d, 28a, 29b, 30a, 31a, 32c, 33d, 34b, 35c, 36c, 37c, 38b, 39b, 40d, 41a, 42a, 43a, 44c, 45c, 46a, 47c, 48c, 49a, 50d, 51d, 52a, 53e, 54c, 55a...