The scientists have been making the experiment for half a year, but they ____ (not succeed) yet.
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His wife ______ (hope) to catch the last train, but she was too late.
The dinner was the most expensive meal we ______ (ever have).
In this area men take off their hats when a woman ______ (enter) the room.
After driving for thirty miles, Mary suddenly realized that she ______ (drive) in the wrong direction.