___ in thought, he almost ran into the car in front of him.
On hearing a great noise, Mike looked forward through the window _____ what happened outside the room.
We hadn't met for 20 years, but I recognized her_____ I saw her.
There were many more people who got injured in the big fire than _______.
This robot is supposed to save a lot of labor, but it remains a problem if it ______.
George applied for the position three times ______ he finally got it.