expensive [?k?spens?v]
adj. 费钱的；昂贵的
The diamond ring is more expensive than the silver ring and the gold ring.
钻石戒指比银戒指和金戒指都要贵。
故expensive指物品贵.(带有比较之意)
valuable ['v?lju?bl]
a. 有价值的, 贵重的, 宝贵的, 可估价的
[经] 有价值的, 可估价的, 贵重的
The computer is valuable
指物品贵(带有评估之意)
precious [?pre?s]
adj.
1. 珍贵的
precious words
珍贵的话
2. 珍爱的
My precious!
我的宝贝儿！
precious 指事物(带有喜爱珍爱之意)