一般放在be动词之后或者助动词与主要动词之间,但sometimes、often等还可以放在句首或句尾,usually可放在句首,once可放在句尾,twice、three times等一般放在句尾.如：Sometimes I get up early.(我有时起得早)/ The workers usually have lunch at the factory.(工人们通常在厂里吃午饭) / Take this medicine twice a day.(这种药一天吃两次) 1.频率副词是表示与次数,频率有关的副词,如: always(总是),usually(通常),frequently（经常） often （经常）sometimes(有时),seldom(不常),rarely（极少）,never（从不） once(一次),twice(两次),等. 2.频率副词用在be动词后. It is usually hot in summer. 夏天天气通常是热的. 3.频率副词用在主要动词前. My father usually walks home. 我的父亲经常步行回家. 4.频率副词用在助动词与主要动词之间. I will always love you. 我将永远爱你. 5.频率副词用在ought to之间. You ought often to write to your mother. 你应该常给你母亲写信. 6.在答句中,频率副词必须放在助动词前. Do you often go there? 你常去那里吗? (误)Yes,I do often. 是的,我常去. (正)Yes,I often do. 是的,我常去. 7.never(从不),seldom(很少,不常)用于句首时,句子要用倒装形式以加强语气. Never have I been there. 我从未去过那里. Seldom do I watch TV. 我很少看电视. 频率副词位置记忆口诀：BE后 主动前 助主间 对频率提问用how ofen
