求助GWD 一道题~~ GWD6-Q17: Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve metropolitan Boston. A.Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve B.Concerns about public health have led to the construction of three separate sewer systems between 1876 and 1904 to serve C.Concerns about public health have led between 1876 and 1904 to the construction of three separate sewer systems for serving D.There were concerns about public health leading to the construction between 1876 and 1904 of three separate sewer systems serving E.There were concerns leading between 1876 and 1904 to the construction of three separate sewer systems for serving
答案选A 应该是题目中没有明确的用完成时的标志如since,所以时态不合适的先排除 C没有看出来大问题,不知道是不是不够简洁(用了there be)? D 最后的for表目的不如TO好?