Everything that humans hear is in the form of waves(波). Just as the eye sees light waves in the form of colors, the ear hears sound waves in the form of noises. The ear and the eye turn these different waves into signals that the brain(大脑) can make sense of.
The ears and brain have an amazing ability to recognize(识别) particular sounds. For example, a mother often can tell when her baby is crying even if there are other crying babies in the same room. This is because the sound of her baby’s cry has special meaning to her and the brain has recorded its importance.
The ability to recognize sounds improves with experiences. As the brain receives information about sounds from day to day, it stores the information in its memory. When the brain hears new sounds, it gives meaning to them based on the information already in the memory. This is why certain words or songs can make a person happy. Often it is not the words or songs themselves that cause this feeling. The sounds are connected to happy memories for that person.
Another hearing process controlled by the brain is to decide where a sound is coming from. One ear is usually closer to the source(来源) of a sound than the other ear is. Sound waves are stronger when they reach the ear that is closer. They also reach the closer ear first. The brain recognizes these differences and uses them to decide the location of the source of the sound.
【小题1】Which of the following shows the normal hearing process of a mother hearing her baby crying?
a. The ears receive the sound waves.
b. The mother recognizes her baby’s cry.
c. The baby’s turn the sound waves into signals.
d. The baby’s cry travels in the form of sound waves.
e. The brain connects the signals to the information in the memory.

Miss Evans taught physics in a London school. Last month she was explaining to her class about sound, and she decided to test them to see how successful she had been in her work. She said to them, Now, I have a sister in Washington. If I was calling her on the telephone, and at the same time you were 20 meters away and listened to me from the other side of the street, who could hear what I said earlier, my sister or you? And why?

   The cleverest boy at once answered, “Your sister, Miss Evans, because electricity (电)travels faster than sound waves(波).” That's very good, Miss Evans answered, but then one of the girls put up her hand, and Miss Evans said, Yes, Betty?

    “I don't think so. Betty said, Your sister would hear you earlier because when it's eleven o'clock here, it's only six o'clock in Washington.”

(   )6. Miss Evans was teaching her class __________.

       A. about sound                       B. to hear some strange sound

       C. about electricity                    D. how to say time

(   )7. She wanted to make her students know__________.

       A. whether she could hear her sister in Washington

       B. whether her students could hear her from 20 meters away

       C. which was faster, London or Washington

        D. electricity travels faster than sound waves

(   )8. The cleverest boy thought that___________.

        A. sound waves travel faster than electricity

        B. they would hear her sister in Washington first

        C. Miss Evans's question wasn't right

        D. Miss Evans's sister would hear her earlier

(   ) 9. Miss Evans________.

        A. thought Betty's answer was much better

        B. thought the cleverest boy's answer wasn't so good

        C. was satisfied with what the girl had said

        D. was satisfied with(对...感到满意) what the cleverest boy had said

(   )10. Betty thought the cleverest boy was wrong, because_____________.

       A. clocks in Washington showed a different time from those in London

       B. electricity was slower than sound waves

C. they were only 20 meters away from the telephone

       D. electricity travels as fast as sound waves

【小题1】She insisted on __________ (send) the sick boy to hospital at once.
【小题2】How long ______ he _________ (keep) the book since he borrowed it from the library?
【小题3】We ____________ (learn) over 2,000 English words by the end of last term.
【小题4】I hear that the result of the exam _______________ (announce) next week.
【小题5】Love Ship is about a woman who _____________ (fall) in love with a man when she travels.
【小题6】If the walls of your room _____________ (paint) blue, you’ll feel calm and peaceful.
【小题7】 The Green family ___________________ (have) dinner when the doorbell rang.