基本信息
learning aims: 1.learn words and expressions. 2.increase their vocabulary by learning rules of word formations. learning difficulties and important points: grasp the related usages about words. period one:self-study 1.step (vi) 跨步，踏，踩 （n）脚步，步伐，台阶 e.g. step this way ,please. he stepped down from a helicopter. he took a step forward. 【拓展】in st
