[求助]XY-4-17, 请高人看过来。。。。

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：A

而我选的D, to serve表目的？我怎么觉得用ing表功能更能说得通呢？

to serve表示目的没有错。。。

最大的问题是 concerns并不是物质名词，用there be句型(如果又不是比较结构)肯定是错的。