________the temperature falling so rapidly,we couldn't go on with the experiment.
The reason______ she failed to go to the party puzzled all of the people present.
In the U.S, ______a tip is thought to be polite when paying the bill.
He is the only one of those clerks ________ to the important conference.
When I turned to Tony for help, I found that the more he tried to explain, ___________.
The two boys share the same hobbies but they are quite different _______ personality.