It was in the lab ______ was taken charge of by Professor Harris _______ they did the experiment.
Jumping out of_________ airplane at ten thousand feet is quite _________ exciting experience.
Once a decision has been made, all of us should _________ it.
_______ ,! have to put it away and focus my attention on study this week.
Elephants have their own way to tell the shape of an object and _________ it is rough or smooth.
Scientists generally agree that Earth's climate will warm up over the next 50 to 100 years __________ it has warmed in the 20,000 years since Ice Age.