以must提问的一般疑问句,意为“……必须……吗”.肯定回答用must（必须）,否定回答用needn't或don't/doesn't have to（不必）.如
-Must I finish the work today?我必须在今天之内完成工作吗?
-Yes,you must.是的,你必须./-No,you needn't.不,你不必./-No,you don't have to.不,你不必.