题目

For some time now, Chinese people, under the leadership of CPC, ______ the contents of the Scientific Development Theory in the course of practicing socialism in China. A. had been improving B. have been improving C. were improving D. improved 答案：B下列现象中，①烟雾弥漫；②雪花飞舞；③香气扑鼻；④尘土飞扬．能说明分子在不停地做无规则运动的是    （填序号），我们称之为    现象．