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.

Ex Input:
Sentence1: microscope is used to see small things by biologists by making them appear bigger. 
Sentence2: Something invented by Leeuwenhoek is used to see small things by biologists by making them appear bigger.

Ex Output:
appear


Ex Input:
Sentence1: Crops are plants that are grown for food or other uses. 
Sentence2: insects destroy plants.

Ex Output:
plants


Ex Input:
Sentence1: When ferns are dormant it is as if they are hibernating. 
Sentence2: Some viruses live in a hibernating state inside the body.

Ex Output:

hibernating