WHY DOES THE AUTHOR MENTION A CHINESE TOY

10. - File thứ 1: De va dap an thi thu lan 2, Anh
Tiếng Anh File thứ 1: De va dap an thi thu lan 2, Anh
10. Why does the author mention a Chinese toy? A. To show that helicopter flight was envisioned in ancient times. B. To prove that helicopters were the first aircraft. C. To emphasize to complex design of helicopters. D. To contrast helicopters and fixed wing aircraft. Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.