1. What ambitions do children usually have? 

Well, it all depends. Some children admire people such as scientists, doctors and engineers who make great contributions to society, and they aspire to engage in one of these professions in the future. Some kids have an inborn talent in arts or sports, so they are ambitious to become a painter, singers or top athlete. while others' ambitions may be more related to their study, like achieving excellent academic performance or getting admitted to a prestigious university in the future.

2. Why don't some people havedreams? 

Firstly, this may have something to do with their personality. Some people are easily satisfied with the status quo and have no intention to make any improvements in their study, work or life. Besides, some people used to have dreams, but they met a lot of challenges in pursuing those dreams and got frustrated with them. so they gradually gave up and become aimless people.