@Lim,
Show has quite a few meanings, depending on whether it's used as a verb or noun. I suspect you're looking for the most common meaning which would be to let someone see something. As in " I'll show you my pet hamster."
To show someone up is to ridicule them, or point out their failings, usually publically. It has a very specific meaning.
Helping someone out is also very specific and implies quite a lot of help and quite a lot of hardship. You would help out a homeless person or a victim of a crime. Just helping on its own is not as strong. Helping someone by holding a ladder for them is not the same as helping them out.
If somewhere is closed down it means they've finished doing business for good. If they're closed it may be because it's outside of opening hours, but if they're closed down then they're finished.
Again, all the phrases you have chosen have specific meanings, yet the individual words can have many meanings depending on context.