Both "Dies" and "Diese" + "sind Schlüssel" are acceptable. But we are only displaying one option. "Dies sind .." sounds more natural, even though it is less grammatical acceptable.
Multiple keys are referred to in this scenario (this is why the 3rd person plural of "to be" was used". "Dies[e/] sind Schlüssel." = These are keys. "Das ist ein Schlüssel." = That is a key.
Well, with quite a lot of thinking you can indeed find a situation where "Diese sind Schlüssel" might be acceptable. But DL should not teach such sentences, which very typically occur as translation mistakes (like "Dieses is seltsam, ist es nicht?") as a standard way of wording things.
Here is the situation I spoke of: Together with a fellow researcher you examine metal parts on a UFO crash site. You divert them into classes, and pointing to one class of metal things, you say "These are keys, aren't they? Your colleague is of different opinion. She points to another class, saying: Diese hier sind Schlüssel, nicht die, die du meinst.
Sorry, I cannot find any more normal situation, where any German in his right mind would say "Diese sind Schlüssel."
The normal way to say "These are keys" in German is "Das sind Schlüssel"
I'm lost with this "dies". From what I can search, it's the abbreviated "dieses". And demonstrative pronouns are supposed to be declined as adjectives. And when look for those, the only thing ending in "-es" whether weak or strong and in any case is neutrals. Yet here I have "Schlüssel", which is masculine.
Am I missing something completely? am I looking in the wrong place?
Shouldn't it be "Diese sind Schlüssel"? or "Dieser ist ein Schlüssel"?
I don't understand where this "Dies" is coming from. I note down everything i learn and it's not in my notes. It's not on this page about demonstrative pronouns either on any of the 4 cases or genders; http://www.udoklinger.de/Deutsch/Grammatik/Pronomen.htm#Demonstrativpronomen
It's supposed to be Diese(+optionally some other letter(s) depending on gender and case)
It seems that Schlüssel is always written with ss not ß, but I don't really understand why. I thought that rule was that ss is written as ß after a long vowel, as long as there is no other consonant next to it in the word root. I hear the ü in Schlüssel as a long vowel, so I guess that either I'm wrong about that, or that there is more to the rule than I thought.
I hear and use 'das' in cases like this rather than 'dies'. I know that it's the un-inflected form though.