根据短文内容及首字母提示,补全空格内单词，使短文完整、通顺。（请在答题卡上写出完整单词） 

True friends are hard to find. Often you thought you could believe in someone, b   1   later he or she may let you down (让你失望).

A true friend is someone who will always be there for you. Through good times or b   2   times, they will stand by your side. They will not l   3   you alone when things get difficult. They will accept you without trying to change you. A friend will b   4   new and exciting things into your life and make it richer.

True friends will keep your worst secrets as you will keep t   5  . They will be honest and you can always believe in them. If you talk to someone who you believe in, you don’t have to w   6   about what you may say. We can enjoy this freedom only with friends.

Friendship is a two-way street. To find a true friend and keep the friendship b   7   you, you must do the same thing as well. Be there for your friends when they are in n   8   and share the good times with them. Offer them the same things they give to you. Friendship will break quickly if only one person is giving and p  9   effort into it.

You will find that there is nothing more valuable t   10   having a true friend by your side to share life with, just as someone says, “There is nothing on this earth more to be prized (珍惜) than true friendship”.

室温下，将一定浓度的Na₂CO₃溶液滴入CuSO₄溶液中得到了蓝色沉淀。为了确定沉淀的组成，某研究性学习小组进行了以下试验和研究。

（一）【提出假说】

假设一：两者反应只生成CuCO₃沉淀；

假设二：两者反应只生成Cu(OH)₂沉淀；

假设三：                                        ；

（二）【理论探究】

查阅资料：CuCO₃和Cu(OH)₂均不带结晶水；

K_SP〔CuCO₃〕=1.4×10^-10    K_SP〔Cu(OH)₂〕=5.6×10^-20

若只由此数据结合适当计算来判断，假设              是正确的。

（三）【实验探究】

步骤一：将CuSO₄溶液倒入等浓度等体积的Na₂CO₃溶液中并搅拌，有蓝色沉淀生成。

步骤二：将沉淀从溶液中分离出来，其操作方法为：①过滤 ，②      ，③干燥。           

步骤三：利用下图所示装置，进行定量分析：

① A装置中玻璃仪器的名称是              。

② 仪器组装好后首先要进行的实验操作是                 。

③ 实验结束时通入过量的空气的作用是                  。

④ 数据记录：

利用上述数据初步判断该沉淀的成分是CuCO₃和Cu(OH)₂，在沉淀中二者的物质的量之比为                    。若所得沉淀是纯净物而不是混合物，请写出该物质的化学式                                 。