Which interrogative pronoun should replace the blank space in the following sentence?: I wonder ____ dog knocked our garbage can over.
You can insert the pronoun " which " or " whose " in this sentence.
You might think that " what " would be a correct pronoun, but "what" is not specific enough for this example.
The question implies that there are certain known dogs, in the neighborhood, say, and the speaker wants to know which one of them did it.
"What" is more general. You could use it in a sentence like:
What kind of dog is that?, or
What part of speech is it?
You could also use " whose " in this sentence, as in:
I wonder whose dog knocked our garbage can over.
Here, the speaker knows the dogs and their owners, and wants to know who the guilty party is.