Lesson 21,How can we go to Beijing ,Lets review,An airplane,is,fast,slow,Lets Play,A train,is,faster than,but,slower than,a bus,an airplane,Lets go to Beijing by plane, Mum ! Planes are fast,No, Li Ming. I want to take a bus,A bus is slow ! I dont want to go by bus,Lets take a train ! A train is slower than a plane but faster than a bus,A: Lets go to Beijing by plane, Mum ? Planes are fast ! B: No, Li Ming. I want to take a bus. A: A bus is slow ! I dont want to go by bus ! B: Lets take a train
