Question

Something terrible has happend , hasn´t it ?

or

Something terrible has happend , haven´t they ?

Answer 1

The correct answer is something terrible has happened. It would probably be better to say, "nothing terrible has happened" rather than "something terrible hasn't happened." Like missyasmine said, something is singular, so it takes a singular verb.

If you wanted to make the sentence plural, you could say, "some terrible things have happened," or "no terrible things have happened." It would depend on the content of the conversation.

Answer 2

hasn't it!

Answer 3

just the first one( hasn't it? ) is correct. *it* here is referring to the *something* that might have happened. there is no *plural thing* that would justify using *they* :-). I hope it's helpful.

Answer 4

Something terrible has happened, hasn't it ?  - the first one is correct.

I agree with missyasmine, the use of "they" in the second sentence is not proper unless in the first part you have mentioned someone or a bunch of people. For example:

The prisoners have escaped last night, haven't they?