"Our school's gymnasium is very large" 的英语表达是 "Our school's gym is big."
gymnasium 是一个拉丁词，意思是 "健身房" 或 "体育馆"。在现代英语中，gym 是它的缩写形式，主要用于表示这类建筑物。
例句：
"I'm going to the gym to work out." (我要去体育馆锻炼。)
"The school's new gym is state-of-the-art." (学校的新体育馆是最先进的。)
"The gym is closed for maintenance this week." (这周体育馆关闭维护。)