题干

下列关于“使用显微镜”的做法,正确的是(   )

A:显微镜里的物象若不够清晰,应调节粗准焦螺旋

B:当室内光线较暗时,要用凹面反光镜和大光圈

C:若视野中的物象在左上方,我们想把它移到视野的中央,应该向右下方移动

D:低倍镜换成高倍镜观察植物细胞时,视野变暗,细胞数目变多

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B

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    Probably no other musical instrument is as popular as the guitar around the world. Musicians use the guitar for almost all kinds of music. Country and western music would not be the same without a guitar. The traditional Spanish folk music called Flamenco could not exist without a guitar. The sound of American blues music would not be the same without the sad cry of the guitar. And rock and roll music would almost be impossible without this instrument.

    Music experts do not agree about where the guitar was first played. Most agree it is ancient. Some experts say an instrument very much like a guitar was played in Egypt more than 1,000 years ago. Most experts say that the ancestor of the modern guitar was brought to Spain from Persia sometime in the 12th century. The guitar continued to develop in Spain. In the 1700s it became similar to the instrument we know today.

    Many famous musicians played the instrument. The famous Italian violins Niccole Paganism played and wrote music for the guitar in the early 1800s. Franz Schubert used the guitar to write some of his famous works. In modern times Spanish guitarist Andres Segovia helped make the instrument extremely popular.

    In the 1930s, Les Paul began experimenting to make an electric guitar. He invented the solid-bodied electric guitar in 1946. The Gibson Guitar Company began producing its famous Les Paul Guitar in 1952. It became a powerful influence on popular music. The instrument has the same shape and the same six strings (弦) as the traditional guitar, but it sounds very different. Les Paul produced a series of extremely popular recordings that introduced the public to this music. Listen to this Les Paul recording. It was the fifth most popular song in the United States in 1952. It is called “Meet Mister Callaghan.”