Is past tense correct here?
What is the difference between the following:
Didn't you know there was an election today.
Didn't you know there is an election today.
Isn't the second one ungrammatical?
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In the first sentence the intent of the asker is not to get an answer from you, but rather to provide you with a piece of information.
What the asker actually saying is: "There was a tunderstorm today."
The second sentence makes sense if you reword it as follow: "Didn't you know there is a thunderstorm now?"
In this case the asker actually say: "There is a thunderstorm now."