Learn Hardcore Chinese: hěnduō tóngxué xiàkè yǐhòu qù jùhuì, kěshì wǒ xiǎng huíjiā xiūxi. - Many classmates go to parties after class, but I want to go home and rest.

Breakdown of hěnduō tóngxué xiàkè yǐhòu qù jùhuì, kěshì wǒ xiǎng huíjiā xiūxi.

Why is 很多 used before 同学? Can I just say 很同学?

很多 means “many / a lot of” and is used before a noun to show a large quantity:

很 by itself usually means “very” and is used before adjectives, not nouns:

You cannot say 很同学 to mean “many classmates”; that’s ungrammatical. You need 很多同学 or just 同学们 (the classmates).

Does 同学 mean “student” or “classmate”? Why isn’t there a plural ending like 们?

同学 literally means “person who studies together with you”, so its most direct meaning is “classmate / schoolmate.”

But in daily speech, when students talk to each other, 同学 can also be used like “student” in some contexts, especially in addresses:

Chinese usually does not mark plural on nouns if the context already makes it clear.

很多同学 already tells you there are many people, so adding 们 is unnecessary.
You could say 很多同学们, but it sounds redundant and is usually avoided.
同学们 (without 很多) is common when addressing a group:
- 同学们，好！= Hello, students / classmates!

What does 下课 mean exactly? Is it a verb or a noun?