求助

miafy

GWD6-Q17:

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

 BETWEEN AND 不是在一段时间内吗,为什么不用完成时啊,答案是A

AlienX

construction是在1876 and 1904之間發生, 而led是在construction完成前一定結束啦.  就是說led這個action不可能在現在還在發生...所以不可能用have led.