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: Enveloped viruses make their own membranes. 
Sentence2: Some viruses make their own membranes.

SOLUTION: make

PROBLEM: Sentence1: Insects spread disease and destroy crops. 
Sentence2: insects destroy plants.

SOLUTION:
Insects