it may be many years before the situation in that area improves.请翻译,而且为什么用before?

it may be many years before the situation in that area improves.请翻译,而且为什么用before? It may be many years _______ the economic situation improves.A) when B) that C) after D) beforeIt may be many years _______ the economic situation improves.A) when B) that C) after D) before这里为什么不能用when it may be 5 or 10 years away.( ） It may be many years ______ we meet again.A.after B.before C.since.请问选哪个答案,并说明理由. pollution has become a worldwide problem,it may be many years ( )the situation improvesA.after B.before C.as D.since为什么 It start many years How many years to forget you I don't know .May be people may live_____(be)200 years old in many years.用括号内所给词的适当形式填空 There are too many people on the earth.In 100 years,there may be no r____for even one more person. ( )a few years' time ,it will be covered ( ) many thousand of trees.填介词 it may be a mistake, may it be known that many years later, you may have forget me. 什么意思 一直没多懂的英语题：关于before和until!经常在完形填空里做到关于选until还是before的题.比如说：But it may still be many years ( )this problem could finally be solved.这道题选before.给的简析是“到这个问题 At the monent,it may be difficult to imagine,but many people believe that we will live on the plane will it be many years ___ we can live a rich and happy lifeAwhen B after C until D before For many people the world in fifty years' time will be very different from how it is now. Nobody knows exactly how many years it will be--Chinese football team enters the final stage of theWorld CupAbefore Buntil