after coming into the world?

Or do newborns simply prefer more to fewer? The same experiment, but with three spots shown before two, shows the same return of interest when the number of spots changes. Perhaps it is just the newness? When slightly older babies were shown cards with pictures of objects (a comb, a key, an orange and so on), changing the number of objects had an effect separate from changing the objects themselves. Could it be the pattern that two things make, as opposed to three? No again. Babies paid more attention to squares moving randomly on a screen when their number changed from two to three, or three to two. The effect even crosses between senses. Babies who were repeatedly shown two spots became more excited when they then heard three drumbeats than when they heard just two; likewise(同样地) when the researchers started with drumbeats and moved to spots.

60．The experiment described in Paragraph 1 is related to the baby's ______ .

A．sense of hearing.

B．sense of sight.

C．sense of touch.

D．sense of smell.

61．Babies are sensitive to the change in______.

A．the size of cards.

B．the colour of pictures.

C．the shape of patterns.

D．the number of objects.

62．Why did the researchers test the babies with drumbeats?

A．To reduce the difficulty of the experiment.

B．To see how babies recognize sounds.

C．To carry their experiment further.

D．To keep the babies' interest.

63．Where does this text probably come from?

A．Science fiction.

B．Children's literature.

C．An advertisement.

D．A science report.

C

Eating too much fatty food，exercising too little and smoking can raise your future risk of heart disease．But there is another factor that can cause your heart problems more immediately: the air you breathe．

Previous studies have linked high exposure(暴露) to environmental pollution to an increased risk of heart problems，but two analyses now show that poor air quality can lead to heart attack or stroke (中风) within as little as a few hours after exposure．In one review of the research，scientists found that people exposed to high levels of pollutants (污染物)were up to S% more likely to suffer a heart attack within days of exposure than those with lower exposure．A separate study of stroke patients showed that even air that the U．S．Environmental Protection Agency (EPA) considers to be of