Question

They ___________ (clean) their room before I called them.
A) cleaned
B) cleaning
C) clean
D) had cleaned​

Answer 1

they cleaned their room before i called them

Answer 2

Resposta:

D) had cleaned​

Explicação:

They _had cleaned_ (clean) their room before I called them.

Eles tinha limpado o quarto deles antes que eu os chamassem

Temos 2 frases no passado, uma ocorrendo antes que a outra.

A que ocorreu primeiro vai no Past Perfect. Então HAD + participio.

Portanto letra D