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.

Q: Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: dew is formed when cooling  over night.

A: dew
****
Q: Sentence1: if an object is black then that object absorbs all visible light. 
Sentence2: Something is black if it absorbs visible light and doesn't reflect.

A: light
****
Q: Sentence1: the color of leaves on deciduous trees usually changes in the autumn season. 
Sentence2: Common deciduous trees are the oak, elm and beech.

A:
deciduous
****