The worried general was looking at the map when the idea of the enemy’s attack might be launched ______dawn ______ his mind.

1. A.
   at; crossed
2. B.
   at; to cross
3. C.
   before; came across
4. D.
   after; went over

The worried general was looking at the map when the idea of the enemy’s attack might be launched ______dawn ______ his mind.

　 A. at; crossed　 　　　　　　　　　　　　　B. at; to cross　 　　　

C. before; came across　 　　　　　　　　　 D. after; went over