【重点语法】1. 频率副词: always, usually, often, sometimes, never频率副词在句中通常放在实义动词之前, be动词或助动词之后。常用于一般现在时态中。2.“次数”的表达方法一次 once， 两次twice，三次或三次以上：基数词+ times, 如：three times, five times3. how often“多久一次”问频率，回答常含有频率词组或短语。常见的how疑问词：1）How soon 多久（以后）How soon will he be back?他多久能回来？He will be back in a month. 他一个月后能回来。2）how long “多久”How long did it take you to clean the house? 你打扫房子用了多久？It took me half an hour to clean the house. 我打扫这房子用了半小时。3）How many+名复How much+不可名“多少” 问数量（how
