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