She was dancing while someone substituted at the piano.她在跳舞,别人代她弹钢琴.Glass blocks are sometimes substituted for ordinary bricks.有时,玻璃砖被用来代替普通的砖.He substituted for the worker who was ill.他顶患病的工人干活....
She was dancing while someone substituted at the piano.她在跳舞,别人代她弹钢琴.The synthesis methods of melatonin, related tryptaminetryptamine derivatives and substituted indoles are discussed.从人工合成的角度综述了美乐托宁及有关化合物色胺、色胺衍生物及吲哚衍生物的制...