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