1)shall用于第一人稱，常被will 所代替。

will 在陳述句中用于各人稱，在爭求意見時常用于第二人稱。

Which paragraph shall I read first.

Will you be at home at seven this evening?

2)be going to +不定式，表示將來。

a. 主語的意圖，即將做某事。

What are you going to do tomorrow?

b. 計劃，安排要發生的事。

The play is going to be produced next month。

c. 有跡象要發生的事

Look at the dark clouds, there is going to be a storm.

3) be +不定式表將來，按計劃或正式安排將發生的事。

We are to discuss the report next Saturday.

4)be about to +不定式，意為馬上做某事。

He is about to leave for Beijing.

注意：be about to 不能與tomorrow, next week 等表示明確將來時的時間狀語連用。