It takes years of school to develop math skills, but learning about numbers starts earlier than you might think. Now according to a new study, at three months, babies have already started acquiring a concept (概念) of “how much”.
Previous research had suggested that very young babies can tell when the number of objects (物体) in a group has changed. But the babies in these studies were simply reacting generally to the fact that something had changed, they suspected.
Researchers of Harvard University studied 36 babies, all three months old. During the tests, each baby wore a hat with sensors (传感器). The babies watched a series of images on a computer screen. They showed the same object, such as a cartoon character. For a while, the number of the objects in the pictures didn’t change. Then the images began to display a different object, or a different number of one of the objects the babies had previously looked at. As soon as something changed, the babies’ brains responded with a specific pattern of electrical signals, which would be recorded by sensors.
By analyzing these signals, the researchers discovered that one part of the brain (near the top on the left side) responded when the object in the image changed. A different part of the brain (lower and on the right side) responded when the number of objects in the image changed. This was not the area of the brain that is involved in attention. That suggests that the babies’ brains are doing more than just reacting to a change in what they’re seeing – they actually seem to be able to tell number changes from other types of changes.
Numbers and amounts are important concepts in our lives. Even though babies are years away from adding, subtracting (减), multiplying, and dividing, their brains seem to be preparing for a time when they finally will.
Why were hats with sensors used in the study?

A．To record the images on the computer screen.

B．To remind babies of the changes of numbers.

C．To record the electrical activity of each baby’s brain.

D．To help babies concentrate on the computer screen.

What does the underlined word “They” in the third paragraph refer to?

A．Babies involved in the study.

B．Sensors worn by the babies.

C．Numbers marked on the objects.

D．Images shown on the computer screen.

Which part of the brain is responsible for responding to the changes of numbers?

A．The top.

B．The left side.

C．The lower and the right side.

D．The upper and the left side.

The last paragraph mainly implies that           .

A．babies are in fact cleverer than they are thought

B．it is impossible to understand human brain completely

C．numbers play the most important part in people’s lives

D．the ability of babies remain a mystery to scientists

The purpose of the study is to prove that          .

A．math skills should be developed as early as possible

B．numbers are easier for babies to judge than images

C．babies really do have some sense of numbers

D．babies can react differently to what they see