That, This, These, Those (Das, Dass, Diese)?
Is it not as necessary to differentiate between these words in German as it is in English because it seems like Diese and Das can mean any of them and I know I have seen dass before but I forgot how to use it.
I would like to see this Q&A reposted as an insight (or better yet, to be included in the text note of the lessons, if there's a way to tell Duolingo to do so), since this is a main theme of the Nominative Pronouns' lessons, but is also so poorly explained upfront. Also the explanation is very clear and complete.
You have to differentiate between singular and plural forms:
dieser Apfel - diese Äpfel
dieses Mädchen - diese Mädchen
With a feminine noun, singular and plural forms are the same "diese": diese Frau - diese Frauen
The differentiation in distance to the speaker i.e. "this" vs. "that" and "these" vs. "those" could be mimicked by "dieser" vs. "jener" (sing.) and "diese" vs. "jene". But Germans are not particularly picky on that and jener/jenes/jene are seldomly used in spoken language.
The word "dass" (or the older form "daß") on the other hand is not a pronoun at all, but a conjunction corresponding to the english conjunction "that" as in
Er weiß dass Menschen lügen. He knows that people lie.
Basically rephrasing what SlowLarry said above, it is my understanding that "this vs. that" is not really an issue to concern yourself with. In English, we are using "this / these" to be close to us and "that / those" to be farther away. Typically, if I wanted to describe THE specific computer that is a distance from me, merely referring to it as "Der Computer da" (the computer there) should be sufficient.
Since modern spoken German is not particularly concerned with the distance, let us focus on "this or these." "This or these" merely differentiates between singular and plural, so...
Notice that it simply mimics the last-letter changes of definitive articles (der, die, das) from singular to plural in nominative case, except the beginning is "dies-". Hope this helps!
Dieser Tisch - Diese Tische = This table - These tables
Diese Frau - Diese Frauen = This woman - These women
Dieses Spiel - Diese Spiele = This game - These games
To those asking, as long as you are in nominative case, this will be so. Changing case affects an identifier (like diese) in the same manner that the article (like das) would be affected. So, in the example for "dieses Spiel ist gut" is "this game is good" while "diese Spiele sind gut" is "these games are good."
Now, for use in the dative case, das becomes dem and die becomes den, so you would say "...mit diesem Spiel" for singular (with this game) or "...mit diesen Spielen" for plural (with these games). Hope that helps!
Here you go (I don't know how to move the whole conversation here so please like this comment, it will be very helpful for everybody): http://www.duolingo.com/comment/1252496$comment_id=1256577
Ja. Here I write down the full table of 'diese' (I learnt this from the 1st lesson where learning Die): MA NEU FEM PLU Normanative dieser dieses diese diese Accusative diesen dieses diese diese Dative diesem diesem dieser diesen Genetive dieses dieses dieser dieser
Hope not mistyping.
I think I've catched the clue here. Who is the subject? Wife= Die Frau. What's the case? Nominative because we don't perform any action on the subject, we are just naming it with possesion (as the subject belongs to me). So, "that" can be treated, as I read from the posts of SlowLarry and casezer0, as "diese". So your translation is correct. Now, after practicing a lot (because I'm struggleling with this too) I've noticed that duolingo sujests that another correct translation is "das ist meine frau". But I haven't understand why they use "das", although the use of "diese" it's clear for me now.