一瓶水倒掉一部分，则剩余部分的水的质量______，体积______，密度___

溴化钙可用作阻燃剂、制冷剂，具有易溶于水，易吸潮等性质。实验室用工业大理石（含有少量Al³⁺、Fe³⁺等杂质）制备溴化钙的主要流程如下：

完成下列填空：

（1）上述使用的氢溴酸的质量分数为26%，若用47%的氢溴酸配置26%的氢溴酸的氢溴酸500ml，所需的玻璃仪器有玻璃棒、                。

（2）已知步骤Ⅲ的滤液中不含NH₄⁺。步骤Ⅱ加入的试剂a是        ，控制溶液的pH约为8．0的目的是         、           。

（3）试剂b是         ，步骤Ⅳ的目的是                 。

（4）步骤Ⅴ所含的操作依次是                 、            。

（5）制得的溴化钙可以通过如下步骤测定其纯度：

①称取4．00g无水溴化钙样品；②溶解；③滴入足量Na₂CO₃溶液，充分反应后过滤；④    ；⑤称量。若得到1．88g碳酸钙，则溴化钙的质量分数为                   （保留两位小数）。

若实验操作规范而测定结果偏低，其原因是                 。

Directions: Read the following passage. Complete the diagram by using the information for the passage.

Write NO MORE THAN 3 WORDS for each answer.

     Since it was founded a year ago, the babysitting pool has become increasingly popular in the United States.

More and more mothers have joined it and have benefited from it. What attracts them most is the idea that you

pay your babysitter not in cash, but in paper cards. When you join the babysitting pool, you are given thirty

cards, which are worth 30-minute babysitting time each. For each half an hour while you are gone, th

e babysitter gets paid one card.

     There are rules regulating this service. You should not watch more than three kids at a time including your

own. On big holidays, such as Christmas and Thanksgiving, the babysitter should be paid twice as much,

which means two cards for every half an hour. When you leave the babysitting pool, you should return all the

cards. If you are out of cards, you cannot use money instead. You should have to baby-sit for others to earn

enough cards so that you will have them handy when you yourself need a babysitter.

     Many mothers think highly of this service. It keeps children in constant touch with one another, and makes

life easier for the mothers. Since in most cases, the babysitter is the mother who watches other kids at her

own home, it is still possible for her to do her own things while the kids play with each other. In fact most

mother babysitters find that their own kids are less of a monster and easier to watch when they are around

other playmates. Moreover, since the babysitting pool service does not involve money, it will not be a financial

loss to the family.

     In the past year, the babysitting pool has helped so many mothers with their work that they all think that it

is indeed a good community service worth keeping.

天然气脱水装置甘醇的耗量与吸收塔上捕雾网的工作状况无关。

患者男性，15岁，恒牙，磨牙远中关系，上颌略前突，下颌基本正常，UI-SN：105°，前牙深覆、深覆盖Ⅱ度，上下牙弓Ⅱ度拥挤。

矫治进行到第二阶段，打开咬合作用较好的是（）。

A.0.016不锈钢丝

B.0.018×0.022NiTi丝

C.0.019×0.025NiTi丝

D.0.018×0.022不锈钢丝

E.0.019×0.025不锈钢丝

F.0.016NiTi丝

明末出现的一部总结造园经验的著作是什么