ex) I love it.

'Love it' is pronounced as a linking sound.

'Love it' are pronounced as a linking sound.

'Love' and 'it' are pronounced as a linking sound.

'Love' and 'it' is pronounced as a linking sound.
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Which ones are correct? Do I have to use a singular verb or plural verb?

I think the first and third one are correct.

The first is best; the third is OK. The others are incorrect. You're right!

=)

The correct sentence is:

'Love' and 'it' are pronounced as a linking sound.

In this sentence, the subject 'Love' and the pronoun 'it' are connected by the conjunction 'and', indicating that they are both referring to the same thing and should be treated as plural. Therefore, we use the plural verb 'are' instead of the singular verb 'is'.