Mark the letter A, B, C, or D on vour answer sheet to indicate the correct answer to each of the following questions.
Trả lời cho các câu 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 dưới đây: