快速答案
antes 表示在参照点之前；atrás 表示后面，接时间数量时表示“……以前”。
可靠的方法是先判断这个词在句子里的功能，再翻译。
每个词的作用
antes
before or earlier
Use antes for an earlier position in time relative to an event.
atrás
behind or ago
Use atrás for a position at the back, or elapsed time after a quantity.
如何选择
- antes: Choose antes if the sentence points to an earlier position in time relative to an event.
- atrás: Choose atrás if the sentence points to a position at the back, or elapsed time after a quantity.
例句
Cheguei antes do almoço.
I arrived before lunch.
Ele saiu dois dias atrás.
He left two days ago.
常见误区
Dois dias antes needs another reference point. For “two days ago,” say dois dias atrás or há dois dias.
放到语境中练习
从你的真实生活中选一个句子，写两遍：一次用 antes，一次用 atrás。如果两个版本都可以，说明意思怎样变化。