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: riding a bike does not cause pollution. 
Sentence2: riding a bike does not release particles.
Example Output: bike

Example Input: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: items properties are the same as the materials the item is made of.
Example Output: made

Example Input: Sentence1: Saturated fats are solid at room temperature. 
Sentence2: Saturated fats make butter solid at ambient temperatures.
Example Output:
Saturated