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

• I have a pen pal from Canada.我有一个来自加拿大的笔友。
• My pen pal likes to draw pictures.我的笔友喜欢画画。
• Does your pen pal live in the city?你的笔友住在城市里吗？
• She writes to me every week.她每周给我写信。
• I am going to visit my pen pal next summer.我打算明年夏天去拜访我的笔友。