题目内容：

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Child development

People live much longer than most other animals, so human childhood also lasts a long time. Unlike baby animals, human children need many years to learn how to live on their own as adults. As children’s bodies grow, so do their minds.    1.

There are several stages of child development. Infancy (婴儿期) is the most helpless stage. Over their first year infants gradually learn to roll over, sit up, crawl (爬), and take their first steps with someone helping them. As they grow out of infancy, babies begin to make sounds similar to words.

The toddler stage (学步期) begins when a baby starts to walk, usually at about the age of 1. Most children also start saying words at about this time. As toddlers grow they become stronger and have more control of their bodies. Their thinking skills also improve.     2.    They like to copy what other people say and do.

Between the ages of 3 and 5, children are in the preschool stage. Children learn many important skills during this stage. They learn to share and to take turns.     3.   Playing with others helps them learn how to get along with all kinds of people.

Starting school marks a new stage. Children’s minds develop quickly as they learn reading and writing. They also learn more about cooperating with others.

Between 9 and 12 years old, children are preteens.     4.   They become better at controlling their behavior. Preteens also understand how to be helpful to others.

5.   As preteens become teenagers, they move one step closer to becoming adults and living on their own.

A. This growth is called child development.

B. As their bodies grow stronger, they try sports.

C. They learn how to play simple games with rules.

D. During this stage they become much more independent.

E. The end of the preteen years marks the end of childhood.

F. They slowly start putting words together to make sentences.

G. Preteens also become more aware of the world beyond their home.