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: mountains are formed by earthquakes. 
Sentence2: Mountains are formed by moving plates.
Example Output: are

Example Input: Sentence1: Refrigerators are major users of electricity. 
Sentence2: Keeping food fresh for a long period of time requires a lot of electricity.
Example Output: electricity

Example Input: Sentence1: Predators are the animals that eat prey. 
Sentence2: Being a predator requires catching prey.
Example Output:
Predators