问题
选择题
____ the days he had spent with his American friends, he couldn’t help_____.
A．Keeping up; smile
B．Staying up; smiling
C．Looking back on; smiling
D．Looking at; to smile
答案
答案：C
考查非谓语动词，第一空考查现在分词作状语，用Looking back on回顾，第二空考查现在分词作宾语，can’t help doing情不自禁作某事，句意：回顾他与美国朋友在一起的那些日子，他情不自禁笑了。所以选C。