how come don't need to s after the word train?

Answer 1

You can...it depends what you are trying to say

for example...Those trains are nice!

Answer 2

This question makes no sense. Read this for me: how come don't need to s after the word train?
Now, tell me, does that make any sense to you?

Answer 3

You need the "s" if you use "train" as a noun, you don't if you use it as a verb.