He wants to become a doctor when he grows up.

他长大后想成为一名医生。

同一单元的其他句子

• She enjoys reading books in the library every weekend.她喜欢每个周末在图书馆看书。
• To finish the project on time, we need to work together.为了按时完成项目，我们需要一起工作。
• The teacher told the students to stop talking in class.老师告诉学生们不要在课堂上说话。
• Having finished his homework, he went out to play.完成作业后，他出去玩了。
• The boy running in the park is my younger brother.在公园里跑步的那个男孩是我弟弟。