单选题 Did the entertainer prepare his jokes before the program, or______them as he went along?
【正确答案】 C
【答案解析】[解析] 根据句意“即兴讲笑话”可知，本题只有C项improvise“即兴创作，即兴表演， 临时准备”符合题意。因此本题选C。