题目内容：

    The baby is just one day old and has not left hospital yet. She is quiet but alert(警觉的). The researchers have placed a white card with two black spots on it twenty centimeters from her face. She stares at it carefully.

A researcher removes the card and replaces it by another one, this time with the spots differently spaced. As the cards change from one to the other, her gaze（凝视） starts to lose its focus until a third card is presented. The third card has three black spots on it. Her gaze comes back: she looks at it for twice as long as she did at the precious card. Can she tell that the number two is different from three, just 24 hours 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 a little 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 beats of the drum than when they heard just two; similarly, when the researchers started beats of the drum and moved to spots.

1.What's the experiment described in Paragraph 1 mainly about?

A.The baby's sense of sight. B.The baby's sense of touch.

C.The baby's sense of smell. D.The baby's sense of hearing

2.Babies are alert to the change in                             . '

A.the size of cards B.the color of pictures

C.the shape of patterns D.the number of objects

3.Why did the researchers test the babies with beats of the drum?

A.Because they wanted to keep the babies' interests.

B.Because they wanted to carry the experiment further.

C.Because they wanted to see how babies recognize sounds.

D.Because they wanted to reduce the difficulty of the experiment.

4.Where does this passage probably come from?

A.Children's literature. B.An advertisement.

C.Science fiction. D.A science report.