填空题 Choose the correct headings(15 points).The following passage has six paragraphs i~vi. Choose the correct heading for each paragraph from the list of headings in the box. Write the correct number a-f in the underlined blanks below.

填空题 Paragraph i 1

填空题 Paragraph ii 1

填空题 Paragraph iii 1

填空题 Paragraph iv 1

填空题 Paragraph v 1

填空题 Paragraph vi 1