中国改变工业落后的面貌，开始向社会主义工业化迈进的标志性事件是（    ）

如图电路，E=8V，r=1Ω，R₀=3Ω，变阻器R的可调范围为0～10Ω，S闭合，

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.