2 If Sarah ............................. (learn) Portuguese, she would have enjoyed her stay in Brazil more.

2. If Sarah had learned Portuguese, she would have enjoyed her stay in Brazil more.

Это условное предложение третьего типа (Third Conditional). Оно описывает нереальные ситуации в прошлом. В первой части (if clause) используется Past Perfect, а во второй части (main clause) - would have + Past Participle.

Ответ: If Sarah had learned Portuguese, she would have enjoyed her stay in Brazil more. Third Conditional