A、B、C三个数的平均数是45,A、C两数的平均数是27,则B是( )。

题型:填空题

问题:

A、B、C三个数的平均数是45,A、C两数的平均数是27,则B是(     )。

考点:统计(平均数)整数的四则混合运算及应用题
题型:填空题

Reading comprehension.

     In 1826, a Frenchman named Niepce needed pictures for his business. But he was not a good artist, so

he invented a very simple camera. He put it in a window of his house and took a picture of his garden. That

was the first photo.

     The next important date in the history of photography (摄影) was in 1837. That year, Daguerre, another

Frenchman, took a picture of his reading room. He used a new kind of camera in a different way. In his picture

you could see everything very clearly, even the smallest thing. This kind of photo was called Daguerreotype.

     Soon, other people began to use Daguerre's way. Travelers brought back wonderful photos from all around

the world. People took pictures of famous buildings, cities and mountains.

     In about 1840, photography was developed. Then photographers could take pictures of people and moving

things. That was not simple. The photographers had to carry a lot of film and other machines. But this did not

stop them, for example, some in the United States worked so hard. Mathew Brady was a famous American

photographer. He took many pictures of great people. The pictures were unusual because they were very lifelike

(栩栩如生的).

     Photography also became a kind of art by the end of the 19th century. Some photos were not just copies

of the real world. They showed ideas and feelings, like other art forms.

Answer the following questions according to what you read.

1. Who took the first photo?

    ____________________________________________________________________________

2. The Daguerreotype was a kind of photo, wasn't it? 

    ____________________________________________________________________________

3. If a photographer wanted to take pictures of moving things in 1840, what did he have to do? 

    ____________________________________________________________________________

4. Why was Mathew Brady famous? 

    ____________________________________________________________________________

5. When did photography become a kind of art? 

    ____________________________________________________________________________

题型:填空题

气分证的证候不包括()

A.发热汗出

B.脉数有力

C.口渴心烦

D.舌红苔黄

E.微恶风寒

题型:填空题

具有固精缩尿功效的药物是()

A.补骨脂、益智仁

B.山茱萸、金樱子

C.覆盆子、桑螵蛸

D.海螵蛸、乌梅

E.五味子、五倍子

题型:填空题

紧急放风阀有三个作用位,(),(),()。

题型:填空题

在当前使用奔腾处理器的PC机,图形加速卡最好连在( )。

A.ISA总线上

B.PCI总线上

C.EISA总线上

D.AGP总线上

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