You will be given two sentences. One of them is created by paraphrasing the original one, with changes on an aspect, or using synonyms. Your task is to decide what is the difference between two sentences. Types of change are explained below:
 Tense: The verbs in the sentence are changed in tense.
Number: Plural nouns, verbs and pronouns are changed into single ones or the other way around.
Voice: If the verbs are in active voice, they're changed to passive or the other way around.
Adverb: The paraphrase has one adverb or more than the original sentence.
Gender: The paraphrase differs from the original sentence in the gender of the names and pronouns.
Synonym: Some words or phrases of the original sentence are replaced with synonym words or phrases. Changes in the names of people are also considered a synonym change. Classify your answers into Tense, Number, Voice, Adverb, Gender, and Synonym.
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Question: original sentence: Although they ran at about the same speed , Sue beat Sally because she had such a good start . paraphrase: Although they ran at about the same speed , Sue and Joan beat Sally and Mary because they had such a good start .

Answer: Number


Question: original sentence: Fred covered his eyes with his hands , because the wind was blowing sand around . He opened them when the wind stopped . paraphrase: Fred covered his eye with his hand , because the wind was blowing sand around . He opened it when the wind stopped .

Answer: Number


Question: original sentence: The scientists are studying three species of fish that have recently been found living in the Indian Ocean . They appeared two years ago . paraphrase: The scientists were studying three species of fish that have recently been found living in the Indian Ocean . They appeared two years ago .

Answer:
Tense