6、当(表示义务责任,口语中多用shouldWeshould/ought tohelp each other andlearn from each other in our work.She is your mother, so youought tosupport her.We ought to go and see Mary tomorrow, but I don’t think we will1.第一、三人称疑问句中表示“请求或征求对方意见Shallwegotothezootomorrow.2.第二、三人称陈述句中YoushallhavethebookafterIread