【简答题】The two friends who had not met for a long time were so __________ in conversation as to be unconscious of the lapse of time. [A] engaged [B] absorbed [C] focused [D] devoted
【简答题】Long conversation list en to a long conversatio n and choose the best answer to each ques tion you hear.
【判断题】表面活性剂加入到水中时,表面活性剂分子优先在水中形成胶束。
【简答题】在一个干燥洁净的茶杯中放入优质山泉水,快满时小心一颗一颗加入洁净沙子,会看到什么现象?若这时在液面上加一滴表面活性剂,情况又将如何?
【判断题】表面活性剂加入到水中时,表面活性剂分子优先在水中形成胶束。