some expressions
I went to the woods and soon spotted a squirrel minding its own business doing whatever squirrels do. I gave chase and began peppering marbles at it until finally it jumped onto a tree, ran to the top and found itself trapped. I kept blasting away and grazed it a couple of times so it was only a matter of time before I would knock it down.

What's the meaning of “peppering marbles", "blast away"," a matter of time", and "knock it down"?

Question

some expressions
I went to the woods and soon spotted a squirrel minding its own business doing whatever squirrels do. I gave chase and began peppering marbles at it until finally it jumped onto a tree, ran to the top and found itself trapped. I kept blasting away and grazed it a couple of times so it was only a matter of time before I would knock it down.

What's the meaning of “peppering marbles", "blast away"," a matter of time", and "knock it down"?

Answer

Personally, I have never heard the phrase "peppering marbles" before. However, given the context, it means "throwing something."

"Blasting away" means that the person kept throwing things at the squirrel.

"A matter of time" means that the next part of the sentence was definitely going to happen. The person kept throwing things at the squirrel. Because of this, one of those things would eventually hit the squirrel.

"Knock it down" means to hit an object, making it fall from where it is. The person hit the squirrel, making it fall down from the tree.