给出一道英语语法题，要求填写空白部分，并解释填入的单词形态和用法。
One of my favorite ___ is playing soccer.
One of my favorite activities is playing soccer.

"Activities" is a noun and used to describe a thing that a person does. In this context, it refers to the things that the speaker likes to do. The word "favorite" is used to describe the speaker's preferences.