Itwas_____thechiefengineercame_____webegantheexperiment.
A.not until; that B.not until; then C.until; that D.until; when正确答案A
Itwas_____thechiefengineercame_____webegantheexperiment.
A.not until; that B.not until; then C.until; that D.until; when正确答案A