阅读文章，回答问题。

      有一句话是须臾不可忘的，就是“君子爱财，取之有道”。万万不可见财起意，生出些个歪门邪道来。还有一句话，总是让咱们沾沾自喜，就是咱们读书写书，觉得挺充实，也挺有“财富”的，咱也可以自为小“财主”。而且，咱们除了知识“财富”之外，有限的那点儿“财富”，都是干净的，不怕半夜敲门。

      半夜来敲我家房门的，不是来读书论画的，就是收电费的白天没见到我家的人。

应该如何理解“君子爱财，取之有道”一句话的含义？

化学小组探究镁、铁、铜三种金属的活动性顺序，设计了下图所示实验方案．

（1）试管乙中观察到的现象是____，反应的化学方程式为____ ．

（2）同学们经讨论后认为该方案可以优化，____试管的实验是多余的．

（3）去掉多余的实验，同学们将另两只试管中反应后的物质倒入同一大烧杯中，一段时间后过滤，

向滤渣中加入稀硫酸，有气泡产生，则滤渣的成分可能是____ ．

    Yesterday it was Sharon's birthday, but she had no special plans, so she decided to go home after work.She left the office arid while she was walking down the street，she was1her friends.They usually remembered her birthday but they had forgotten it for the first time this year.“I think that's2because all of them are busy at work.I guess they will call me tomorrow as it is Saturday, ”she said to herself.Then she3that she was hungry, so she bought some food in a supermarket.And when she came out of the supermarket，she saw an old woman selling4.She bought some roses(玫瑰)from her and left.

    After she got home，she took a shower.And then she had some food.“Now I feel much happier,”she said.“If5remembers my birthday, I will celebrate it by myself.”Suddenly the doorbell (门铃)rang.It was 11：00 p.m.She was surprised 6her husband was on a business trip.“7could it be?”She thought and went to open the door.

    “Happy birthday! ”A group of her friends and her husband were there! Also their hands were full of colorful packages(包裹).She couldn't8her eyes. She had everybody9her and many nice gifts.It was the most10moment (时刻)of her life.“I'm really happy to have such thoughtful friends like you.Thank you all!”Sharon said excitedly.