Each one quickly realized the need for defense, especially in the air.
I looked him over and realized for the first time that the chief was an old man.
I realized for the first time that he wasn't a young man.
And he realized for the first time that she wasn't a child.
However, she doesn't realize his love for her and is about to get married to another person.
Or rather I had realized for the first time that this was so.
At that moment she realized for the first time how good it felt to help others.
The effort made her realize for the first time how hot it was.
Her father looked up and seemed to realize for the first time that she was there.
I have realized for the second time in my life how big our planet is.