词汇	It is a sad thing
释义	It is a sad thing. 真是不幸的事。
随便看	excitation system stabilizer excitation-system voltage response ratio excitation table excitation teaching method excitation technique excitation technology excitation teehnigue excitation temperature excitation tendency excitation, thermal excitation threshold excitation thyristor rectifier cubicle excitation time excitation-time imaging condition excitation time of a fluorescent screen excitation transfer excitation transfer theory excitation transformer excitation trigger excitation unit excitation variable excitation vector excitation voltage excitation voltage regulator excitation volt-ampere