precious

　　adj.珍奇的;珍稀的;寶貴的;珍貴的;受珍愛的;被珍惜的;

　　adv.強調(diào)極少或太少;

　　[例句]After four months in foreign parts, every hour at home was precious

　　在國外呆了4個月后，在家的每一刻都是寶貴的。

　　比較級：more precious

　　最高級：most precious

　　priceless

　　adj.無價的;極珍貴的;極重要的;極有趣的;

　　[例句]They are priceless, unique and irreplaceable.

　　它們是獨一無二、不可替代的無價之寶。

　　Human life is _____，so he makes every effort to make many___discoveries in science.

　　A.precious，valuable

　　B.priceless，valuable

　　C.priceless，precious

　　答案：B