地球上有各种不同的环境，有水域，有____，有炎热的地方，也有寒冷的地方，几乎到处都有生物存在．

完形填空。

    Jack is my classmate. He is my good friend. He is 1 American boy. He is from 2. He is short. He has a round face and    3 big brown eyes. His 4 is not black. It is blond (金黄色的). Tom likes English. He can speak a little Chinese, too. He goes to school 5 foot.

    We usually 6 our homework at school. We clean our classroom 7 every Friday. Usually, Tom 8 the blackboard and I sweep the floor. Our favourite sport is basketball. Sometimes we 9 in the playground. We 10 at 4.30. We both like our teachers and classmates.

选出读音正确的一项是（）

板块构造学说认为，地壳中比较活跃的地带是（　　）