Unit 2 Keeping Healthy Topic 3 Must we do exercise to prevent the flu? Section AThe main activities are 1a and 2. 本课重点活动是1a和2。Ⅰ. Teaching aims and demands 教学目标1. Learn some useful words and expressions:talk with, hurry, hurry up, question, go ahead, spread, among, do exercise, do some cleaning, all the time, have to, keep away 2. Go on learning the modal verbs “should” and “must”:(1)What should we do to fight SARS?(2)We should keep our rooms clean.(3)W..