“明天的”怎么翻译

直接用tomorrow's
I'm going to do some preparation for tomorrow's class.

另外，虽然汉语表达“明天的”为定语，不过我觉得翻译成英文的时候‘明天’作为副词也可以。
I'm going to do some preparation for the class/lesson tomorrow.

lessons for tomorrow
tomorrow's lessons
都可以用的。

I am going to prepare tomorrow's lessons.

I had to prepare for my lesson on tomorrow.

Tomorrow of

I have to prepare the lessons of tomorrow.