More highways have been built in China,making it much easier

句意：更多公路在中国建成,使得人们从一地到另一地变得更方便.Making为定语从句的省略,等于
More highways have been built in China,which makes it much easier for people to travel from one place to another.
再问： 为什么作为定语从句的省略，要用ing
再答： 前一句表达的“更多公路在中国建成”的事实是make的逻辑主语，关系为主动，故省略后用ing形式表达主动；如果前后关系为被动，则可以用动词过去分词形式：The cake made by grandma tastes really good.(= The cake which was made by grandma tastes really good.)