free fall

自由落体

fraudulent, fraudulently, fraught, fray, frazzle, freak, freak-out, freakish, freakishly, freakishness, freaky, freckle, freckled, free, free agent, free and easy, free association, free balloon, Free Church, free enterprise, free from, free house, free kick, free lance, free love, free of, free port, free speech, free trade, free verse, free vote, free wheel, free will, free-for-all, free-hand, free-handed, free-lance, free-liver, free-living, free-load,