课件16张PPT。Unit 3 We should obey the rules.Lesson 17 cross the streetwait forpick flowerskeep off the grasslook outlitterspittake good care of young childrenWe must obey the traffic rules.You mustn't cross the road.You must wait for the green light. must,情态动词，“必须”，否定式mustn't ，“不许”。 Make sentences. must/mustn'tMake orders.2.Look out!3.You mustn't cross the street now.4.You must wait for the green light.6.You mustn't spit on the ground.7.You mustn't litter.8.You must keep off the grass.1.You mustn't pick the flowers.5.You must take good care of young children.Listen and read.1.Look out!2.You mustn't cross the street now.3.You must wait for the green light.4.You mustn't spit on the ground.5.You mustn't litter.6.You must keep off the grass.7.You mustn't pick the flowers.8.You must take good care of young children.What should we do ?Say goodbye!
