TASK DEFINITION: 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.
PROBLEM: Sentence1: Some mollusks are nearly microscopic. 
Sentence2: Some squids are nearly microscopic.

SOLUTION: Some

PROBLEM: Sentence1: Limestone caves displaying stalactites. 
Sentence2: Limestone caves are formed by depositions.

SOLUTION: Limestone

PROBLEM: Sentence1: a gasoline lawn mower converts gasoline into motion. 
Sentence2: Diesel and gasoline are chemicals.

SOLUTION:
gasoline