We takhave our first class at eight o'clock. We have our first class at eight o'clock.

We take oOur first class is at eight o'clock. Our first class is at eight o'clock.

I like to sleep a long time, but I can't because I have lots of courses and homeworks. I like to sleep a long time, but I can't because I have lots of courses and homework.

“Homework” is uncountable.

I like to sleep a long timwhile, but I can't because I have lots of courses and homeworks. I like to sleep a while, but I can't because I have lots of courses and homework.

not wrong but