为什么knowledge is treasure treasure是不可数的

treasure: [ 'tre? ]
n. 宝物,财富
v. 珍爱,重视,储藏
例句与用法:
1. this museum has many art treasures.
这家博物馆收藏了许多艺术珍品.
2. such a lesson should be treasured in our memories.
这样的宝贵教训应该铭记在心.
3. my dearest treasure!的宝贝儿!
4. i shall always treasure the memory of our meetings.
将永远记住 相聚的情景.
5. our new secretary is a perfect treasure.
新来的秘书十分能干.
6. the police found the lost treasure in an abandoned well.
警察在一口废弃的井里找到了丢失的财宝.
7. knowledge is a treasure, but practice is the key to it.
【谚】知识是宝库,实践是钥匙.
8. the gallery is a treasure trove of medieval art.
这个画廊是中世纪艺术的宝库.