Question

As Karen drove her Mustang up to the take-out window, it began to rattle

Answer 1

What began to rattle; the Mustang, or the take-out window?

Answer 2

@huzai: I see this is your first post to OpenStudy.
At first glance, it seems to me that this post should go into the English section.
Would you mind posting your sentence there instead of here (in Mathematics)?
Thanks.