Which of the following describes what synonyms must have in common?

• They must be the same part of speech.
• They must sound the same.
• They must be nouns.
• They must mean different things.

Réponse: They must mean different things.

The correct answer is: They must be the same part of speech.

To determine which of the options describes what synonyms must have in common, we must understand the concept of synonyms. Synonyms are words that have similar meanings, but they are not required to sound the same, be nouns, or mean different things. The key requirement for synonyms is that they must be the same part of speech.

So, to determine if two words are synonyms, you can follow these steps:

1. Identify the two words you are comparing.
2. Determine their parts of speech. For example, if one word is a noun and the other is a verb, they are not synonyms.
3. If both words belong to the same part of speech (e.g., both are nouns, both are adjectives, etc.), then they can potentially be synonyms.
4. Lastly, consult a dictionary or thesaurus to confirm if the words have similar meanings.

Remember, synonyms are words that have similar meanings but can be different in terms of their spelling, pronunciation, and meaning.

The correct answer is: They must mean different things.