快速答案
assistir 强调作为观众观看；comparecer 强调到场出席。
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
assistir
to watch or attend as an audience
Use assistir for viewing a film, program, lecture, match, or performance.
comparecer
to show up or be present
Use comparecer for being physically or officially present at a scheduled place or event.
如何选择
- assistir: Choose assistir if the sentence points to viewing a film, program, lecture, match, or performance.
- comparecer: Choose comparecer if the sentence points to being physically or officially present at a scheduled place or event.
例句
Assistimos à palestra pela internet.
We watched the lecture online.
Todos os candidatos devem comparecer à entrevista.
All candidates must attend the interview.
常见误区
Someone can comparecer a uma reunião without watching a performance, and can assistir online without physically showing up.
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 assistir，一次用 comparecer。如果两个版本都可以，说明意思怎样变化。