4-f
n. [美国英语]；选征兵役制中不及格者免除兵役(者)(指身体、心理、品德等不适于服兵役)的分类
🗣️ 情景例句
We once found a cat.
我们有一次找到一只猫，
It may be even more valuable than money but it tastes awful!
它可能比金钱更有价值，但是味道遭透了。
Some of this heat near the earth's surfact is used to make electricity.
靠近地表的一部分热量已被用来发电。