Prepositions are short words (in English they are words like "on," "of," "around," etc.) that show relationships between different parts of the sentence (i.e. verbs with nouns or nouns with nouns). They can't be changed and are not declined. The normally come before the noun they are connected with.
Even though they are small words, they can drastically change the meaning of a sentence. And using prepositions isn’t always so simple. Directly translating them only helps sometimes, since they are most likely used differently than in your native language. You need to learn which prepositions are used in which situations.
Prepositions also determine the case the noun is in.
There are different types of prepositions: locative, modal, temporal, and causal.
Locative prepositions are related to location or movement.
Locative ⇒ related to location
Questions: Wo? Wohin? Woher?
A: „Wo bist du?“
B: „Ich bin vor dem Kino. Ich warte neben dem blauen Mercedes."
The most common locative prepositions: an, auf, aus, bei, hinter, in, neben, von, vor, zu.
Here's a list of all locative prepositions, along with their meaning, use, and the case they require: Locative Prepositions.
Temporal prepositions are related to time. When did it happen? How long did it last?
Temporal ⇒ related to time
Questions: Wann? Wie lange?
A: „Wann musst du arbeiten?“
B: „Ich muss von 8 bis 17 Uhr arbeiten.“
The most common temporal prepositions: an, ab, bis, gegen, in, nach, seit, um, von, vor.
Here's a list of all temporal prepositions, along with their meaning, use, and the case they require: Temporal Prepositions.
Modal prepositions describe how or in what way something happens.
Modal ⇒ related to how / in what way
A: „Wie kommst du zum Bahnhof?“
B: „Ich fahre mit dem Auto.“
The most common modal prepositions: auf, für, gegen, mit, ohne, statt.
Causal prepositions describe the reason for or result of an action. Why did it happen?
Causal ⇒ related to the reason for / results of an action
Questions: Warum? Wieso? Weswegen?
A: „Wieso musst du heute länger arbeiten?“
B: „Wegen der vielen kranken Kollegen.“
The most common causal prepositions: anlässlich, aufgrund, dank, trotz, ungeachtet, wegen, … zufolge.
Sometimes prepositions are combined with a definite article (der, die, das, …).
For these preposition + article combinations, you should always combine them into the contraction:
In informal speech, the following prepositions are often combined with the articles. However, following formal grammar rules, only the separated form is correct.
If the preposition and article are separated, it's not an article anymore. It's a demonstrative pronoun.
Prepositions don't just relate different parts of the sentence to each other. They also have another important role:
Prepositions determine the case of the noun that follows them. ALWAYS!
Some prepositions ALWAYS use the same case. I've summarized them in lists by case:
There are also prepositions that change case depending on how they are used: Two-Case Prepositions.
Everything about prepositions related to time: Temporal Prepositions
How to form questions with prepositions: Questions with Prepositions
Some verbs have prepositions complements: Verbs with Prepositions