burden

n.负担，负重；负荷，载重；义务，责任

bundle, bung, bung-hole, bungalow, bungle, bungler, bungling, bunion, bunk, bunker, bunkum, bunny, Bunsen burner, bunting, buoy, buoyancy, buoyant, buoyantly, bur (also burr), burble, burdensome, bureau, bureaucracy, bureaucrat, bureaucratic, bureaucratically, burette, burgeon, burger, burgh, burgher, burglar, burglar-alarm, burglar-proof, burglary, burgle, burgomaster, Burgundy, burial, burial service,