快速答案
em vez de 可用于任何替代；当两个选项互为相反时，ao invés de 最准确。
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
em vez de
instead of
Use em vez de for substitution: one action, person, or thing takes another’s place.
ao invés de
as the opposite of
Use ao invés de for a genuine reversal or opposition between directions, states, or results.
如何选择
- em vez de: Choose em vez de if the sentence points to substitution: one action, person, or thing takes another’s place.
- ao invés de: Choose ao invés de if the sentence points to a genuine reversal or opposition between directions, states, or results.
例句
Fomos de ônibus em vez de carro.
We went by bus instead of by car.
Ao invés de cair, a temperatura subiu.
Instead of falling, the temperature rose.
常见误区
Broad use of ao invés de is common, but em vez de is always the safer expression when there is substitution without opposition.
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 em vez de，一次用 ao invés de。如果两个版本都可以，说明意思怎样变化。