三道英语语法题,要解释,谢谢
1.some farmers are still using tools and methods_____back to prehistoric times
为什么选dating不是to date
2.there was a terrible noise______the sudden burst of light
为什么选following不是followed
3.______as amember of the committee,i can testify that our system is in need of improvement
为什么选having served不是served