Since the road is wet this morning, ________ last night．

1. A.
   it must rain
2. B.
   it must be raining
3. C.
   it must have rained
4. D.
   it must have been rain

Since the road is wet this morning, _____ last night.

A.     it must rain  B. it must be raining  C. it must have rained  D. it must have been rain

 Since the road is wet this morning, _____ last night.  

A. it must rain 　　　　　　       B. it must have rained  

C. it must be rained 　　　　      D. it must have been rained