On the previous page all the subjects were the first element of the sentence, but subjects can also come later in the sentence. The important thing is not where the subject comes in the sentence but that the subject of an active verb is the doer. Here are some sentences where the subject is not the first item:
How many pencils did John buy?
What did Karen send to her girlfriend?
The book I sent to my father was just published.
That jackass I just can’t stand.
In France they speak French
Dammit, why does the post office always mangle my mail?