介绍:
Day 32.
That xenon could not FORM chemical compounds was once believed by scientists.
科学家曾相信：氙气是不能形成化合物的。
Xenon 美 [ˈzinɑ:n] n, xian 氙气
Xenon and krypton are not retained by the body so they have little effect.
氙和氪不能在人体内停留所以对人体影响很小。
例题：科学家一度认为这些疾病是不可治愈的。
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