@mihocomo,
English grammer stinks.
My question is which version of English are you trying to learn?
Australian English is more relaxed and ussually people won't care in common talking.
While alternativly British English is supper strick on every noun and its usage.
Americans vary, if they complain just tell them thats how you were taught.
The proper usage actually depends on how your using it. Example: 1) The scale is over there. 2) Yes, I have the scales.
Example one is meant for 1 scale. While Example 2 is meant for multiple or complex scales.
Reply if you need more information.
Try a translator to read this if you have trouble. The grammer of English goes subject to predicet compared to Japanese where (if I'm not mistaken) it goes predicet to subject.
please reply.