1.Paragraph①（） 2.Paragraph②（） 3.Paragraph③（） 4.Paragraph④（） 5.Paragraph⑤（） A. What is the function of audio courses? B. What is the function of flash cards? C. What is the function of traditional courses? D. What are the most useful tools for language learning? E. What is the function of computer-aided courses? F. What can help you a lot with your language learning? 下列选项正确的是（）。