每当朋友们聚在一起，他总是滔滔不绝地讲起他那些收藏邮票的爱好。

Whenever friends gather, he always talks endlessly about his stamp collecting ___hobby.

小男孩用他的木马玩具在客厅里假装自己是牛仔。

The little boy pretended to be a cowboy on his ___hobbyhorse in the living room.