Question

Most people know Alexander Graham Bell invented the telephone. But not many know about another talking device (equipment) he invented just four years later，in 1880. He called the device the photophone.

"Photophone" comes form the Greek words for "light" and "sound". The photophone did not use electricity to carry sound over wires between two people. That' s what a telephone does. Instead,

the photophone used a beam of sunlight traveling through the air. With his invention, Bell could actually transmit(传递)human speech on a beam of light. To do so，he spoke close to a thin mirror that was reflecting sunlight. The vibrations(颤动)of his voice caused the mirror to vibrate，and the vibrating mirror caused the light to vibrate. The vibrating light hit a light-sensitive cell in a receiver placed some distance away. The cell changed the light patterns into electrical signals. Earphones changed the signals back into sounds.

Bell believed that his idea of talking on a beam of light would prove to be important. He often called the photophone his greatest invention. Even though the photophone depended on a source of energy that was not constant一the sun―Bell wasn' t a bit discouraged. He felt sure that people would one day talk using beams of light.

Two much more recent developments made Bell' s dream come true. In 1960 ，a scientist built the laser. A laser produces a highly concentrated beam of light. Shortly afterward, other scientists developed a new kind of optical fiber. The optical fiber is a glass thread. The new fiber could carry light beams long distances―as far as several miles.

(   ) 1. According to Bell's own opinion,        is his greatest invention.

A. telephone    B. optical fiber C. photophone    D. laser

(   ) 2. What does "That" refer to in the underlined sentence?

A.  Using a beam of sunlight traveling through the air.

B.  Using electricity to carry sound over wires between two people.

C.  Transmitting human speech on a beam of light.

D.  Light and sound.

(   ) 3. Which statement is true about Bell，s invention of photophone?

A.   The photophone depends on a constant source of energy.

B.   The photophone is based on the invention of the telephone.

C.   Earphones are used to change light into sounds.

D.   The laser and the optical fiber are helpful for Bell' s invention.

Answer 1

1. C细节理解题。从第三段"He often called the photophone his greatest invention"可知答案是photophone_u

2. B逻辑推理题。从第二段"The photophone did not use electricity to carry sound over wires between two people. That's what a telephone does"可以推出telephone是靠电流来传播声音的。

3. D综合判断题。最后一段提到"Two much more recent developments made Bell, s dream come true"， 而接下来介绍的两项发明是"the laser and the optical fiber"，所以推断出D项正确_D从第四段的"Even though the photophone depended on a source of energy that was not constant―the sun―Bell wasn't a bit discouraged"，可知A选项错误。B项内容文章没有提到。根据第二段"Earphones changed the signals back into sounds"，可知C项错误。