将两个词合成一个词1. play+ground=playground2. school+bag=schoolbag3. foot+ball=football4. wash+room=washroom5. walk+man=walkman6. note+book=notebook7. police+woman=policewoman8. week+end=weekend9. grand+parents=grandparents10. snow+man=snowman11. police+man=policeman12. water+melon=watermelon13. class+room=classroom14. bed+room=bedroom15. home+work=homework16. house+woek=housework17. air+conditoner=air-conditioner18. book+shelf=bookshelf19.ice+cream=ice-cream 20.tree+planting=tree-planting。