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Science is a kind of knowledge which is a very useful tool in solving the technical problem of industry, agriculture, warfare and medicine. To understand the width and depth to which science can be applied to the material and spiritual problems that confront the individuals and nations requires an understanding of what science really is.
The word science comes to us from a Latin word, scire, which means “to know”. Then, in a broad sense, science is simply what we know; the total of all human knowledge. But the definition of science as all human knowledge would not be a workable one，for it is obvious that there are different types of types of knowledge. The kinds differ according to how the knowledge was obtained，and also according to what frame of experience it fits. What we know of the arts，literature, law, religion，and technical knowhow, are more or less separate funds of information. They have little to do with what we commonly call science.
Science is also called natural science to distinguish it from other branches of learning. Science is concerned with nature，that is，with knowledge of the characteristics and operations of any and all natural things and happenings. Science embraces all of nature, and expresses our best ideas of how natural phenomena are related to each other and are to be formed into what is called the universe.
Science has many characteristics，and to understand what science is requires a detailed examination of these properties and peculiarities. A number of writers have asserted that science is really only a method——the scientific method. Such a definition is an oversimplification, but it is certain that the scientific method plays an important role in determining the nature of scientific knowledge.
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Lots of people pretend that they never read advertisements, but this claim is hardly believable. It is almost impassible not to read advertisements these days. Just think what fun they often provide! Imagine what a bus and railway station would be like without advertisements? Would you enjoy gazing helplessly at a blank wall while waiting for a bus or train? Would you like to read a daily paper closely-printed with columns of news? A cheerful，witty advertisement makes such a difference to a drab wall or newspaper. We must not forget，either，that advertising makes a positive contribution to our packets. Newspapers, radio or television stations could not subsist without this source of revenue. The fact that we pay so little for our daily paper，or can enjoy so many programs on air is due entirely to the money spent by advertisers. Just think what a newspaper would cost if we had to pay its full price! Another thing we mustn't forget is the "small ads" which are in virtually every newspaper. What a tremendously useful service they perform for the community! Just about everything can be accomplished through these columns，for instance，you can find a job，buy or sell a house，announce a birth，marriage or death. It's the advertisement among the advertisements.
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Few great names in music spell as much magic to the average concert-goer as that of Tschaikovsky. In almost every musical form will be found a work of his ranking high in popularity. And quite deservedly so. Tschaikovsky's music is filled with a warm humanity and stirring drama. The themes and feelings are easy to grasp. The personal，intimate note is so strong in this music that we find it natural，while listening to the Pathetic Symphony or the Nutcracker Ballet Suite，for example，to share Tschaikovsky's joys and sorrows. His music seems to take us into his
