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: Fully cooking oysters kills the bacteria. 
Sentence2: Fully cooking oysters can prevent illness.
Example Output: Fully

Example Input: Sentence1: if an organism becomes too hot then that organism may die. 
Sentence2: a plant can collapse if it gets too hot.
Example Output: hot

Example Input: Sentence1: creating paper requires cutting down trees. 
Sentence2: Trees only grow to be cut down.
Example Output:
cutting