_____ he stayed in Germany for half a year and he will go to Germany______ again. [ ]

A. Before long; before long                      

B. Long before; long before

C. Before long; long before                      

D. Long before; before long

— The terrible accident is under investigation．

— Actually, quicker action _____ those workers trapped in the mine．

A．might have saved

B．must have saved

C．should have saved

D．could have saved