Sarah didn't come with us because she had visited this art eschibition before. * a) Simple present / Present perfect b) Simple past / Past perfect c) Present perfect / Present perfect ​

Resposta final: A frase "Sarah didn't come with us because she had visited this art exhibition before" usa verbos no simple past e no past perfect. A primeira parte, "Sarah didn't come with us," está no simple past, indicando uma ação concluída no passado. A segunda parte, "she had visited this art exhibition before," está no past perfect, que descreve uma ação que ocorreu antes de outra ação passada. Portanto, a combinação correta de tempos verbais usados na frase é b) Simple past / Past perfect.