那个高人可以给我解释一下这道题哪。我选了d,答案是A Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve metropolitan Boston.
- Concerns about public health led to the construction between 1876 and 1904 of three separate sewer systems to serve
- Concerns about public health have led to the construction of three separate sewer systems between 1876 and 1904 to serve
- Concerns about public health have led between 1876 and 1904 to the construction of three separate sewer systems for serving
- There were concerns about public health leading to the construction between 1876 and 1904 of three separate sewer systems serving
- There were concerns leading between 1876 and 1904 to the construction of three separate sewer systems for serving
多谢~~ |