exercise often而为什么不是often exercise?

exercise often而为什么不是often exercise? exercise often而为什么不是often exercise? take exercise often,child这句话为什么用take 而不用 taking或者to take how often do you exercise?中的exercise在此句中是什么词性?为什么?谢谢大家 How often do you exercise? how often do you exercise? we should exercise often.often可以放句尾吗? this is good exercise 为什么不是this is a good exercise ? Every morning I see many people in the park exercising.------------初二下册英语冀教版P4为什么不用:exercise而用:exercising呢?不是说：习惯性经常性用：exercise ( do) 现在正在进行的用：exercising（doing）吗? 问句英语.excuse me,could you please tell me how often为什么不能问how often do you exercise? He is often told not to do something.为什么用something而不用anything啊?不是否定句要变的么. --__do you exercise?--hardly ever A How many tim--__do you exercise?--hardly everA How many times.B How often选A 选B为什么 为什么是exercise one hour a day and live a whole happy life为什么用 exercise不是exercising how often do you exercise等于什么? How often does he ___（exercise）? How often do you exercise?怎么回答 要how often do you exercise作文 How often do you take exercise?