题目

In many countries, ___46___ is not unusual for families of different backgrounds to live together in the shared space. ___47___, in the United States, this idea may still be considered strange. But this type of housing, ___48___(call) co-housing, is gaining ___49__ (popular) in the United States, too. Co-housing complexes are popping up across the country. For many people, this way of life is a relief to the busy modern lifestyle. A co-housing community has ___50___ (private) owned houses and shared land. There is often a “common house” with __51___ kitchen and dining room, meeting向盛有硫酸铜水溶液的试管里加入氨水，首先形成难溶物，继续添加氨水，难溶物溶解得到深蓝色的透明溶液，下列对此现象的说法正确的是A.反应后溶液中不存在任何沉淀，所以反应前后Cu2+的浓度不变B. [Cu(NH3)4] 2+的空间构型为正四面体型C.沉淀溶解后，将生成深蓝色的配合离子[Cu(NH3)4]2+D.在[Cu(NH3)4] 2+离子中，Cu2+给出孤对电子，NH3提供空轨道