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: items properties are the same as the materials the item is made of.
Example Output: made

Example Input: Sentence1: Plants live just about everywhere on Earth. 
Sentence2: epiphytes live everywhere on earth.
Example Output: everywhere

Example Input: Sentence1: Oxygen is just one substance transported by the blood. 
Sentence2: Substances needed by active muscles are transported by blood.
Example Output:
substance