'Teaching am I' is a dreadful, terrible and incorrect English expression, 'I'm teaching' is just okay. Think of this, 'I am a teacher, teaching history or whatever subject. 请别把英语学死了！！！
强调在教学中。 是加强语气。
答：I haven't window molding catalogs on hand. catalogs 产品目录 haven't ~ something ~ o...详情>>
问：working hard vs. hard working
答：there are no defferent.详情>>
