【简答题】Before marriage, younger Americans date each other, that is, they often go out together. Casual dating usually begins in the early s, and in the late s a 1)_______ of steady dating develops. T...
【简答题】洗涤液浓度的测量方法:用____检测洗涤液的浓度。 当使用时,用柔软的绒布将盖板及棱镜表面擦拭干净。将待测液体用____滴于____,合上盖板轻轻按压,将冰点测试仪对向___,旋转目镜使视场内刻度线清晰。读出____在标示板上相应标尺上的数值即可。冰点测试仪的刻度盘1用于____。
【简答题】某研究性学习小组将一定浓度的Na 2 CO 3 溶液滴入CuSO 4 溶液中得到蓝色沉淀。 甲同学认为沉淀可能是CuCO 3 ;乙同学认为沉淀可能是Cu(OH) 2 ; 丙同学认为沉淀可能是CuCO 3 和Cu(OH) 2 的混合物。(查阅资料知:CuCO 3 和Cu(OH) 2 均不带结晶水) Ⅰ、⑴按照甲同学的观点,发生反应的离子反应方程式为______________________; (2...
【简答题】Listen to a short passage concerning American dating and fill in the missing information. Before marriage, younger Americans date each other, that is, they often go out together. Casual dating usually...
【简答题】根据句意及汉语提示完成句子。 1. We must obey the traffic _____ (规则). 2.They often go out for a walk by the _____ (小溪). 3. It's too dark outside.I can't see the blackboard _____ (清晰地). 4. Has anyone got any _____ ( ...
【简答题】(10分)某研究性学习小组将一定浓度Na 2 CO 3 溶液滴入CuSO 4 溶液中得到蓝色沉淀。甲同学认为沉淀可能是CuCO 3 ;乙同学认为沉淀可能是Cu(OH) 2 ; 丙同学认为沉淀可能是CuCO 3 和Cu(OH) 2 的混合物。(查阅资料知:CuCO 3 和Cu(OH) 2 均不带结晶水) Ⅰ.(1)乙同学的观点,你认为其原理是(用离子方程式表示): 。 (2)在探究沉淀成分前,须将沉...
【简答题】They often go out _ __ the evenings. But they don’t go out __ __ Sunday evenings.
【简答题】Before marriage, younger Americans date each other, that is, they often go out together. Casual dating usually begins in the early s, and in the late s a _______ of steady dating develops. The...