四、答案：
1. He was 13 years old when he first had a dream. / 13. / 13 years old. / When he was 13.
2. Because he was too short. 3. 4. / He gave up four dreams.
4. I should never give up my dream and I must work hard. / I should never give up my dream and I must work hard at it. / We should never give up our dreams and we must work hard. / We should never give up our dreams and we must work hard at them.
