or: 或者，否则，常用于否定句中 I don't like apples or bananas. Hurry up or you'll miss the bus. and: 并且，Hurry up and you'll catch the bus.
be to do: 侧重意志,计划,安排I'm to meet him.(含双方事先约好的意思) be going to: 侧重打算,想法 be about to: 表最近的将来,后面不接时间状语