könnten vs sollten
I know they are the höflicher version of können and sollen but Is there a difference between könnten and sollten ? Do they have different uses ? Thanks in Advance ! :)
I'm not completely sure I understand your question, but for startes, können and sollen means something different and are therefore used differently. They are used similar to "can"/"may" and "should" in the English language. Simply put, "könnten" und "sollten" are the inflected forms of the verbs (Konjunktiv).
But since you asked for the different uses, I will elaborate a little.
Besides können (= being able to, know how to, can), können can be used if you want to express a possibility.
"Wir können schreiben." - "We can write."
"Wir könnten heute Abend ins Kino gehen." - "We could go to the cinema this evening."
However, können can also be used similar to the english "may" or "could":
"Kann ich Ihnen helfen?" - "May I help you?" (höflich)
"Könnten Sie mir bitte helfen?" - "Could you help me, please?" (höflich)
"Könntest du mir helfen den Schrank zu tragen?" - "Could you help me carry the cupboard?"
Sollen can also be used differently. It is often used in the "Konjunktiv" like "should" in English:
"Ich sollte jetzt wirklich anfangen zu lernen." - "I should really start to learn now."
Another common usage would be if you want to ask if you should help someone:
"Soll ich dir helfen?" - "Should I help you?"
You should however note that "soll" expresses somewhat of a necessarity and it is more polite if you use "können" if you want to ask if you can help someone. However in the everyday language, it is still used (more for friends and family).
"Soll" can also be used if you're thinking about something you could do (not the possibility! ):
"Soll ich heute Abend ins Kino gehen oder zuhause bleiben?" - "Should I go to the cinema this evening or stay at home?"
Hope this helps. I'm sure you will come across a lot more different usages of "können" and "sollen".