追本溯源

trace back to the source;get at the root of the matter;get to the bottom of

• worm snake
• worms，concordat of
• worms，diet of
• wormwood
• worn
• worry
• worse
• worser
• worship
• worshipful
• worshipfully
• worst
• worsted
• worsted-stocking
• wort
• worth
• worthily
• worthiness
• worthing
• worthless
• worthy
• worth，charles frederic
• wot
• wotan
• wotton，sir henry