以单质碘为催化剂合成了环戊酮乙二缩酮.Cyclopentanone ethylene ketal was synthesized with I _ 2 as catalyst.传统的缩酮化、酯化反应工业上多采用浓硫酸作催化剂.Traditional ketalization and esterification reactions are usually catalyzed by concentrated acid in industr...
a stuffy, airless room空气沉闷不通风的房间This stuffy atmosphere makes me feel dopey.这沉闷的空气使我昏昏欲睡.The stuffy "50s gave way to the swinging "60s.古板乏味的50年代被多姿多彩的60年代所取代。It was a jolly good thing to stop all that stuffy Highgate busi...
你需要些含漱剂来治你的喉痛.You need some gargle to relieve your sore throat.这是含漱剂. 请不要咽下去.This is for gargling only. Please don't swallow it.我看这含漱剂可以治你的喉痛.I think this gargle will relieve your sore throat....