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: Weather today is said to be sunny and clear. 
Sentence2: High pressure systems cause it to be sunny.
[A]: sunny


[Q]: Sentence1: creating paper requires cutting down trees. 
Sentence2: Rainforests are destroyed by logging and all of the trees are cut down.
[A]: cutting


[Q]: Sentence1: To move faster, birds flap their wings more quickly. 
Sentence2: Bird flap their wings more quickly to fly faster.
[A]:
faster