My hobby is collecting 为什么stamps还是collect？

"Collecting stamps can be a fun and educational hobby, as it allows you to learn about different countries' cultures and history through the use of their unique designs."

你学过动名词吗？

动词加ing就是动名词。

动名词的功能是在句子中做主语、宾语或表语。

做主语： collecting stamps is my hobby.

集邮是我的爱好。

做宾语： I like collecting stamps.

我喜欢集邮。

做表语： My hobby is collecting stamps.

我的爱好是集邮，这是动名词的基本功能。