以氟化钾为催化剂, 催化十二烯基琥珀酸酐(DDSA)缩合成螺双内酯化合物.With potassium fluoride as catalyst, spironolactone compound was synthesized from DDSA.研究了双环戊二烯基铁作为燃料添加剂的应用.The application of ferrocene as fuel additive is studied.为此, 我们开展了对含环戊二烯基二硫...
The conductor blew his whistle, and the tram stopped.售票员吹哨子, 电车停了下来.Freda: What can you see a tram or a double - decker ?弗蕾达: 你可以看到有轨电车或 双层?In 1882, London's first electric tram cars went into service...1882 年,伦敦第一辆...