求助：TT GWD 5-17

j96111

Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve metropolitan Boston.

 

1. Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve
2. Concerns about public health have led to the construction of three separate sewer systems between 1876 and 1904 to serve
3. Concerns about public health have led between 1876 and 1904 to the construction of three separate sewer systems for serving
4. There were concerns about public health leading to the construction between 1876 and 1904 of three separate sewer systems serving
5. There were concerns leading between 1876 and 1904 to the construction of three separate sewer systems for serving

答案是A。不知BCDE错哪？

Zeldaw

A is the best

B，现在完成时不对

C，现在完成时不对，led to被分开，表目的应用to serve，而不用for serving

D，there be表达笨重， leading修饰不清

E，there be表达笨重，表目的应用to serve，而不用for serving