What is the difference between in der and in dem? Of course, I know in der is for masculine nouns but I'm not able to understand when we have to use in dem.
Every standard German or English-German dictionary tells you what case goes with a preposition. Frankly, you could have looked that up yourself, but in the case of in, it may be a little tricky. For in, you have two options, as it covers both the English "in" and "into", meaning, the first German in indicates a local position and the second the direction of a change of location. To tell them apart,
the German in corresponding with the English "in" demands to put the noun into the dative case (also called "3. Fall"), and
the German in corresponding with the English "into" demands to put the noun into the accusative case (also called "4. Fall").
In German, definite articles and case endings for dative and accusative in the three genders often look the same, so you have to properly look up what you need in every particular case. I won't give you a grammar table here, as you certainly have one at home, see a few examples instead:
- Du bist im (= in dem) Supermarkt (position, male gender, dative)
- Er ist in der Schule (position, female, dative)
- Ich bin im (= in dem) Haus (position, neuter, dative)
- Sie geht in den Supermarkt (direction, male, accusative)
- Ich fahre in die Schule (direction, female, accusative)
- Sie sind ins (= in das) Theater gegangen (direction, neuter, accusative)
The articles have a declension:
Masculine: der des dem den (N G D A)
Feminine: die der der die
Have a look at declension tabels in your dictionary or grammar or on the Internet.
The optical design of this web page is not the very best but I have not the time to search for more tables.
If you google for "Deklination der die das" you can find more web pages.
- Added: Another website: