Ответ:

John will become an engineer. John won't become an engineer.

Susan will miss her train. Susan won't miss her train.

Nancy will help him with this project. Nancy won't help him with this project.

It will snow the day after tomorrow. It won't snow the day after tomorrow.

He will pass the test. He won't pass the test.

I will call you tonight. I won't call you tonight.

Ответ:

John won't become an engineer.

Susan won't miss her train.

Nancy won't help him with this project.

It won't snow the day after tomorrow.

He won't pass the test.

I won't call you tonight.

Объяснение об образовании отрицательного предложения в Future Simple:

I, you, we, they, he, she, it + will not (won't) +

Для построения отриц. предл. в Future Simple используется вспомогательный глагол will not (или сокращение - won't). В предложениях я использовал won't, т.к. данный вариант был указан в примере. Вы же можете абсолютно везде использовать полную форму  will not.