What's your hobby?

collecting stamps
你问爱好是什么？爱好是不是一件事啊？
一件事是不是属于名词词性啊，所以要用动名词的形式

My hobby is collecting stamps. 我的爱好是收集邮票。

或：I like collecting stamps.
I like to collect stamps.这两种回答是一样的，都是说我喜欢收集邮票。

PS:晕啊,like后面要加不定式to do或者动名词doing，这是固定用法。 相同用法还有love, hate等等。

My hobby is collecting stamps.
或：I like collecting stamps.

Stamp collecting

V-ing作动名词时具有名词的特征,因而在句中用作主语、表语、宾语、定语,有时它可以有自己的逻辑主语,也可以有时态和语态形式。如:

1. 作主语、表语

动名词作主语和表语表示泛指。如:

Tom's not having finished his homework made his teacher angry. 汤姆没有完成作业使老师很生.(主语)

Her job is keeping the offices clean. 她的工作是保持办公室清洁。(表语)

2. 作宾语

动名词常跟在某些动词如enjoy, finish, mind, can't help(禁不住), suggest(建议), advise, consider(考虑), practise, admit, imagine 等以及含介词的短语动词insist on, stop...from, look forward to, pay attention to等后面作宾语。如:

Do you mind my smoking here? 你介意我在这儿吸烟吗?

3. 作定语

动名词作定语时表示被修饰词的