Nowadays more and more people regard traveling as part of their life and Chinese transpor

问题补充：

Nowadays more and more people regard traveling as part of their life, and Chinese transport has been strengthened for the holiday travel .

A. agent

B. diploma

C. dilemma

D. boom

答案：

A. agent

B. diploma

C. dilemma

(答案→)D. boom

解析：名词辨析。A代理人，代理商；B毕业文凭，学位证书；C进退两难的境地；D繁荣，迅速发展；句意：现在越来越多的人把旅游当成生活的一部分，为了让假日旅游迅速发展，中国的交通也被进一步加强了。故D正确。