1) shall用于第一人称，常被will 所代替。
will 在陈述句中用于各人称，在争求意见时常用于第二人称。
Which paragraph shall I read first.
Will you be at home at seven this evening?
2) be going to 不定式，表示将来。
a. 主语的意图，即将做某事。
What are you going to do tomorrow?
b. 计划，安排要发生的事。
The play is going to be produced next month。
c. 有迹象要发生的事
Look at the dark clouds, there is going to be a storm.
3) be 不定式表将来，按计划或正式安排将发生的事。
We are to discuss the report next Saturday.
4) be about to 不定式，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。
