时间状语: always, usually, often, sometimes, every week (day, year, month…), once a week, on Sundays, etc. 基本结构:①be动词;②行为动词 否定形式:①am/is/are+not;②此时态的谓语动词若为行为动词,则在其前加don't,如主语为第三人称单数,则用doesn't,同时还原行为动词。 一般疑问句:①把be动词放于句首;②用助动词do提问,如主语为第三人称单数,则用does,同时,还原行为动词。