在生物分类的等级单位中，最大的和最小的分类单位分别是（　　）

A

    Tom is an eight-year-old student in Grade three. He is not interested in his lessons. He spends most of his time playing basketball. At night, he doesn't sleep until very late in order to play. In the morning, he usually gets up late and hurries to school. Sometimes he sleeps in class.

    Tom's father is worried about his poor schoolwork. He tried to make him work harder. One day, his father said to him, "My boy, if you get one hundred marks in the exam,  I'll buy a new basketball for you." The boy was very happy to hear that.

    The next day  Tom came running home. "Oh, Dad, I got one hundred." He shouted, "I got forty in English this morning and sixty in Chinese this afternoon!"

根据短文内容判断正误。

青春期是多彩的，又是矛盾的。我们在青春期不可避免会遇到的矛盾主要有（）
①独立性与依赖性           ②自制性与冲动性
③好奇性与探究性           ④开放性与封闭性 

完成句子 根据汉语意思完成英语句子，每个空格填一个单词。