Unit 2How often do you exercise,单元语法清,语法精讲频度副词表示动作发生的频率的副词称为频度副词。如always，usually，often，sometimes，hardly ever和never等。这些词表示经常性的动作或状态，而不是某一具体动作，常用于一般现在时中,1频度的区别,2.在句中的位置频度副词在句中常位于be动词、助动词、情态动词之后，实义动词之前。sometimes有时可位于句首或句末。3表示频率的短语有：once/twice a week，three times a day，every week/year等。4对频度副词或短语提问用how often。5频度副词或短语常与一般现在时态连用。eg：I never eat meat.我从不吃肉。Jim usually does his homework in the evening.吉姆通常晚上做作业。Sally often watches TV on weekends.萨莉常常在周末看电视,语法精练一、用方框中所给的单词填空。alwayshardlyusuallyoncesometimes
