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: the moon revolving around the Earth causes the phases of the moon. 
Sentence2: Lets start our discussion of the Moon's phases with the New Moon phase.

SOLUTION: phases

PROBLEM: Sentence1: Distance is measured in meters the SI unit of distance. 
Sentence2: The SI unit of distance is in meters.

SOLUTION: SI

PROBLEM: Sentence1: condensation causes clouds to form. 
Sentence2: Clouds do create rain.

SOLUTION:
clouds

