Choose the best answer A, B, C or D to complete the sentences.Mukai Chiaki, the first female Japanese astronaut, ........... 15 days aboard the space shuttle Columbia in space before it ........ to the Earth on July 23,1994.
A.spent - had returned
B.had spent - returned
C.was spending - was returning
D.spent - was returning
* Đáp án
B
* Hướng dẫn giải
Hành động xảy ra trước một hành động trong quá khứ