一般将来时用于表示将来某个时间要发生的动作或存在的状态，也可以表示将来经常或反复发生的动作。以下是使用will构成的一般将来时的三个例句及其各种句式变化：
基本形式
例句：Tomorrow will be Sunday.
变化：
The rain will stop soon.
We will have a meeting tomorrow.
使用"be going to"结构
例句：We're going to meet outside the school gate.
变化：
Look! It's going to rain.
They're going to leave for Beijing next week.
使用现在进行时表示即将发生的动作
例句：Uncle Wang is coming.
变化：
They're leaving for New York tomorrow.
She's about to finish her homework.
使用一般现在时表示根据规定或时间表预计要发生的动作
例句：The new term starts on August 29th.
变化：
If it doesn't rain tomorrow, we will go out for a picnic.
The train arrives at 5 PM every day.
使用"be+动词不定式"结构
例句：He is to visit Japan next year.
变化：
They are to attend the conference in Paris next month.
She has decided to buy a new car next year.
使用"be about to+动词原形"结构
例句：We are about to leave.
变化：
They are about to start the meeting.
I am about to finish my report.
这些例句展示了will在不同语境下的应用，以及如何通过不同的结构来表达将来时态。希望这些信息对你有所帮助。