Evaluate the similarity between them and classify them into classes from 0-5 as follows:
0 : The two sentences are completely dissimilar.
1 : The two sentences are not equivalent, but are on the same topic.
2 : The two sentences are not equivalent, but share some details.
3 : The two sentences are roughly equivalent, but some important information differs/missing.
4 : The two sentences are mostly equivalent, but some unimportant details differ.
5 : The two sentences are completely equivalent, as they mean the same thing.

Sentence 1: The man is riding a motorcycle down the road. Sentence 2: A man is riding a red motorcycle on the road.
4

Sentence 1: A young man and woman sitting on a bench outside are kissing. Sentence 2: The man and woman sitting on a bench are kissing.
5

Sentence 1: Well, whatever, you are now. Sentence 2: Well, whatever, you're aware of it now.

2