815.If I ______ plan to do anything I wanted to,I'd like to go to Tibet and travel through as much of it as possible.
A.would
B.could
C.had to
D.ought to
816.I was on the highway when this car went past followed by a police car.They _______ at least 150 kilometers an hour.
A.should have been doing
B.must have been doing
C.could have done
D.would have done