Categories

Hey, Oristar! I'm surprised that your space is still for rent! How much would it cost to fill it ?

Anyway; the first use of 'categories' is fine, but the second is un-English. For a natural sentence, I would phrase it thus:

In the industrial product section of the expo, there are many categories of products: automobile-motorcycles, household electrical appliances, water pumps and valves, electric power, etc.

OK?

LOL! I've held a candle to the sun. Your rewriting is absolutely as the same as my original writing. I added the second categories into the sentence of this thread to avoid any possibe ambiguity. Now, it seems the opposite is true.
Thank you dròm_et_rêve (I don't know how to read your name. Eh, tongue in cheeks, drom et reve?)

Ah, but we hardly Ever use the second categories; it is perfectly clear if you do what I have written, whereas, in what you've written, it seems quite muddy, you know?

And just call me Drom! My name is in a nearly-obsolete communication language...

O, and as for being tongue-in-cheek; No! I would love to rent your space!