用方框中所给的短语填在适当的句子中。 at the same time, is crazy about, live up to,  at the age of,  look forward to, 1. I often _______ hearing from my sister. 2. My brother _______ football. He often plays without having supper. 3. Can an elephant _______ 80 years? 4. Hanhan wrote his first novel _______ 17. 5. The young man may be very rude sometimes but _______ he is very kind.