放空炮
fire empty cannons;talk big;spout hot air;indulge in idle boasting;pay lip service
不要～，拿出行動來。Now,none of your empty talk. Let’s see how you act./我當時放了空炮，對形勢作了過分樂觀的分析。I then made some groundless (or pointless)remarks,assessing the situation over-optimistically./我們只能放放空炮。We can only voice some verbal support.