新概念英语第二册Lesson12(18)

3、be to do sth 计划或正式安排将发生的事。 We are to discuss the report next Saturday

Be about to do sth意为马上做某事。 He is about to leave for Beijing. 注意：be about to 不能与tomorrow, next week 等表示明确将来时的时间状 语连用