Definition: Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.
Input: Sentence1: an acid changes the color of litmus paper from blue to red. 
Sentence2: Vinegar changes the color of litmus paper from blue to red.

from