we are looking forward to the Olympic Games,for they have never been held before in this country.

we are looking forward to the Olympic Games,for they have never been held before in this country.
for那儿为什么不用because of .
二、by the end of next year,they will have finished the new stadium.This means they will finish it befor the end of next year.
为什么不是at the end of next year.为什么是befor the end of next year