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 Q]: Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: Condensing is a gas turning into a liquid.
[EX A]: condenses

[EX Q]: Sentence1: Lymphocytes are the key cells involved in the immune response. 
Sentence2: The key cells involved in the immune response produce antibodies.
[EX A]: cells

[EX Q]: Sentence1: a firecracker converts chemical energy into sound. 
Sentence2: a firecracker converts chemical energy into what we hear.
[EX A]:
chemical