PEOPLE DON'T KNOW WHAT CAUSED THE ACCIDENT.A. IT WAS NOT KNOWN W...

48. - File thứ 4: anh12cb_231201916
File thứ 4: anh12cb_231201916

48. People don't know what caused the accident.

A. It was not known what caused the accident.

B. The cause of the accident was not known.

C. It's not known what caused the accident.

D. It's not known what has caused the accident.