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.
The theory he sticks to ______ to be of no use in our studies.
The life he is now used _____ quite different from ours.
He has changed a lot. He _______ not what he _______.
“When did he leave the classroom?” “He left _______ you turned back to write on the blackboard.”
“Shall Mary come and play computer games?” “No, _______ she has finished her homework.”