概括段落大意和补全句子：阅读下面短文，请完成短文后的二项测试任务：(1)从第1~5题后所给的六个选项中为第①~⑤段每段选择一个正确的小标题；(2)从第6~10题后所给的六个选项中选择五个正确选项，分别完成每个句子。 

     ① Most musicians agree that the best violins (小提琴) were made in Cremona, Italy, about 200 years ago. They even sound better than violins made today. Violin makers and scientists try to make instruments (乐器) like the Italian violins, however, they are not the same. Why are these old Italian violins so special? No one really knows. But many people think they have an answer.  

    ② Some people think it is the age of the violins. But there is a problem here. Not all old violins sound wonderful. Only the old violins from Cremona are special. So age cannot be the answer.  

    ③ Other people think the secret to those violins is the wood. It must be from certain kinds of trees. It must not be too young or too old. Perhaps the violin makers of Cremona knew something special about wood for violins.  

    ④ But the kind of wood may not be so important. It may be more important to cut the wood in a special way. Wood for a violin must be cut into the right size and shape. The smallest difference will change the sound of the violin. Musicians sometimes think that this is the secret of the Italians.  

    ⑤ Size and shape may not be the answer either. Scientists make new violins that are exactly the same size and shape. But the new ones still do not sound as good as the old ones. Some scientists think the secret may be the varnish (清漆). It makes the wood look shiny, but it also helps the sound of the instrument. Since no one knows what the Italian violin makers used in their varnish, no one can make the same varnish today. There may never be other violins like the violins of Cremona. And there are not many of the old violins left. So these old violins from Cremona become more and more precious.