1. Fish soon go bad in hot weather.
2. Fish soon goes bad in hot weather.
3. Fish soon go bad in the hot weather.
4. Fish soon goes bad in a hot weather.
Which expression is grammatical?
Sentence 2 is the grammatical one.
The correct expression is:
2. Fish soon goes bad in hot weather.
Explanation:
In this sentence, "fish" is a singular noun, so the verb "goes" should be used instead of "go." Also, "hot weather" is more commonly used without the article "the."