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: if an object is made of a material then that object has the properties of that material. 
Sentence2: If an object is made of a drug, then that object has the properties of that drug.
Example Output: made

Example Input: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: An object is an item in the real world.
Example Output: object

Example Input: Sentence1: Lastly Fire, or light, is perceived through the sense of vision. 
Sentence2: eyes are used for seeing by animals by sense of vision.
Example Output:
sense