手早い答え
sair は主語が去ること、deixar は通常残す物や許す行為を目的語に取ります。
確実な見分け方は、英語から訳す前に、その単語の働きを見きわめることです。
それぞれの単語の働き
sair
to leave or go out
Use sair for the subject moving away from a place.
deixar
to leave something or let
Use deixar for putting someone or something behind, or allowing an action.
選び方
- sair: Choose sair if the sentence points to the subject moving away from a place.
- deixar: Choose deixar if the sentence points to putting someone or something behind, or allowing an action.
例文
Saí de casa às sete.
I left home at seven.
Deixei as chaves na mesa.
I left the keys on the table.
よくある落とし穴
Do not say deixei de casa for “I left home.” That phrase would need another structure and can suggest stopping an activity.
文脈の中で練習する
自分の実生活から文を一つ選び、二回書いてみましょう。一度はsairで、もう一度はdeixarで。どちらも成り立ちそうなら、意味の違いを言葉にしてみましょう。