i am going though some past papers for my exam tomorrow, and im not too sure on how to completly answer this question:

what was the weimar republic? ..by the way, it is only 2marks.

i would really appreciate it if you could help me please

These very small questions carrying a small number of marks are a pain, because they tempt the candidate to write a huge amount, for which they will gain very few marks.

You could write a book on 'What was the Weimar Republic' - BUT DON'T!!!!

I suggest you answer these small-questions with a number of short, factual sentences (even bullet points).
One fact more than the number of marks.

So, for a two-marker on; 'What was the Weimar Republic' you might say the following:
1. set up after the defeat of Germany in WWI and the abdication of Kaiser Wilhelm.
2. genuinely democratic constitution giving the vote for men and women over 21.
3. constitution weakened by Article 48 and proportional representation.

Of course I can't guarantee that this will be accepted as the correct answer, but I suspect it would be much more than is needed to get 2 marks.