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.

Example Input: Sentence1: Dams are very damaging to rivers. 
Sentence2: Creating a lake can be very damaging to rivers.
Example Output: damaging

Example Input: Sentence1: erosion of soil has a negative impact on the environment. 
Sentence2: erosion of soil has a negative impact on forests.
Example Output: erosion

Example Input: Sentence1: tectonic plates being pushed together causes earthquakes. 
Sentence2: plates press together to cause shaking.
Example Output:
plates