Putin says Russia to target U.S. if missiles put in Europe. 老师说新闻标题省略Russia后省略了is,missiles后边省略了were如果是虚拟语气的话那么第一段President Vladimir Putin signaled Russia will aim new weapons at the U.S. if it stations missiles in Europe after quitting a landmark Cold-War-era treaty, amid growing fears of a new arms race. station missiles与put missiles表达一致那么，为什么station用了一般现在式？