26．The underlined word“plunge”in Paragraph 5 means “________”．
A. rise by B. fall by
C. reduce to D. increase to
答案与解析：C 词义猜测题。此处指温度降到－180℃。故选C。
27．Which of the following countries has not explored the moon?
A. India.
B. China.
C. America.
D. The former Soviet Union.
答案与解析：A 细节理解题。根据最后一段可知对月球探测的国家是美国、前苏联和中国，不包括印度。故选A。
28．What's the best title of the passage?
A. Chinese moon rover launched successfully
B. Unmanned spacecraft Chang'e3 landing on the moon
C. China becoming a powerful nation in space exploration
