Jun 19, 2018 - 09:53 PM
I am having similar problems with word placement, but I think I can help with this example. Words like nicht, auch, gut, and viel are placed at the end of a sentence if they apply to the whole sentence; otherwise they go directly in front of the part of the sentence they apply to. In the first case, "You didn't press the green button." could mean you didn't press anything, or that you pressed something, but not the green button. In the first case you are negating the whole sentence, and so nicht goes at the end. In the second case, you place nicht in front of 'auf die grüne Taste.' But both are acceptable.
However, the second sentence ends with 'sondern auf die rote Taste,' so we know you pressed something, just not the green button. Therefore, in this case you don't want to negate the whole first part of the sentence, just 'auf die grüne Taste,' so nicht goes in front of that part of the sentence.
Hope this helps.