Er liegt auf dem roten Bett. In this case 'dem' is an inflected determinant that signalises case number and gender (dative neutre singular). That gives us the weak ending.
The weak endings are pretty much the same if you look at a chart of them. So they signalises case, number and gender weaker than the strong ones do, hence the names strong and weak. I hope you get what I mean.
Am Morgen trinke ich gern starken Tee. In this case there is no determinant. Thus we get the strong declination that better show us the gender, case and number. Here masculine singular accusative.
Gestern war ein sehr schöner Tag. Here we have a determinant (ein) but it is uninflected. That gives us the strong inflection. masc, nom, sg.
The determinants that can be both inflected an uninflected are uninflected only in masculine niminative and neutre nom and acc, (both sg.)
to be continued....
Last edited by Anders
on Thu 14 Jan 2010 12:17 am, edited 1 time in total.