Look out! Don’t get too close to the house ______ roof is under repair.
We prefer to measure our football team's success __________ the number of fans attending rather than the number of games won.
__________ in thought, he almost ran into the car in front of him.
__________ in 1636, Harvard is one of the most famous universities in the United States.
When __________, the museum will be open to the public next year.
The research is so designed that once __________ nothing can be done to change it.