ACE《最简化语法》基础到实战运用四六级留学四合一语法合集2《玩转语法》

快速复习：

will be doing 目前没做，未来一定会做

will have done 目前没完成，未来会完成

will have been doing （eg. Ace will have been writing his book for 6 years by 2015 ) 从现在开始，一直持续发生，发生到某个时间点