电动机运行中，如果电网电压下降到额定电压的85％时，电动机会出现“堵转”现象，此时应

王叔叔家的装修工程接近尾声，油漆工程结束了，经统计，油漆工共做50工时，用了150升油漆，已知油漆每升128元，可以粉刷120平方米，在结算工钱时，有以下几种结算方案：

（1）按工时算，每6工300元；

（2）按油漆费用来算，油漆费用的15%用为工钱；

（3）按粉刷面积来算，每6平方米132元．

请你帮王叔叔算一下，用哪种方案最省钱？

2014年，经合并调整，广州市行政区划从原来的“十区二县级市”变为“（）城区”。

A、12

B、11

C、10

D、13

我国淡水渔业最发达的地区是[ ]

A、东部沿海地区

B、长江中下游地区

C、黄河中下游地区

D、珠江三角洲

单轨小车不得在靠站台一侧的钢轨上推行。

阅读理解。

     Most musicians agree that the best violins were first made in Italy. They were made in Cremona, Italy,

about 200 years ago. These violins sound better than any others. They even sound better than violins made

today. Violin makers and scientists try to make instruments like the old Italian violins. But they aren't the

same. Musicians still prefer the old ones. No one really knows why these old Italian violins are so special,

but many people think they have an answer.

     Some people think it is the age of the violins. They say that today's violins will also sound wonderful

someday. But there is a problem here. Not all old violins sound wonderful. Only those from Cremona are

special. So age cannot be the answer. There must be something different about Cremona or those Italian

violin makers.

     Other people think the secret to those violins is the wood. The wood of the violin is very important. It

must be from certain kinds of trees. It must not be too young or too old. Perhaps the violin makers of

Cremons knew something special about wood for violins.

     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 very carefully. It has to be the right size and shape. The smallest

difference will change the sound of the violin. Musicians sometimes think that this was the secret of the

Italians. Maybe they understood more than we do about how to cut the wood.

     Size and shape may not be the answer either. Scientists measured these old violins very carefully. They

can make new ones that are exactly the same size and shape. But the new violins still do not sound as good

as the old one. Some scientists think the secret may be the varnish, which covers the wood of the violin and

makes it look shiny. It also helps the sound of the instrument. No one knows what the Italian violin makers

used in their varnish. So no one can make the same varnish today.

     There may never be other violins like the violins of Cremona. Their secret may be lost forever. Young

musicians today hope this is not true. They need fine violins. But there aren't very many of the old violins

left. Also, the old violins are very expensive. Recently, a famous old Italian violin was sold for about

US $ 300,000!

1. This passage is about _____. [ ]

A. making violins 　　　　　

B. musical instruments 　

C. scientific ideas 　　　　

D. the old Italian violins

2. The best violins _____. [ ]

A. are made with modern techniques 　

B. were lost many years ago

C. were made in Italy 200 years ago

D. were made by scientists.

3. Some people think that modem violins _____. [ ]

A. will sound better in the future 　

B. will sound worse in the future

C. sound wonderful naturally

D. will never be as old as those from Cremona

4. Violins made today _____. [ ]

A. look the same as the old ones 　

B. sound the same as the old ones 　

C. are better than the old ones　

D. have the same varnish as the old ones