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: condensing causes a liquid to form. 
Sentence2: Air carries moisture that causes a liquid to form.

Ex Output:
causes


Ex Input:
Sentence1: Cnidarians have a hydrostatic skeleton. 
Sentence2: Jellyfish have a hydrostatic skeleton.

Ex Output:
hydrostatic


Ex Input:
Sentence1: pushing on the pedals of a bike cause that bike to move. 
Sentence2: pushing with strokes on a bike cause that bike to move.

Ex Output:

cause