Preview 1-1 The simple present and the present progressive 1-2 Forms of the simple present and the present… 1-3 Frequency adverbs 1-4 Final -s 1-5 Spelling of

单击此处编辑母版标题样式单击此处编辑母版文本样式第二级第三级第四级第五级Grammar Review the usage of –ing form below. Examine the sentences and discuss in what way the structures similar to each other and in what way they are differe