—— Was the driving pleasant when you went to Mexico last summer? —— No, it ____ for four days when we arrived, so the roads were very muddy.
Output is now six times ________ it was before liberation.
"Why did you go to the wrong class, Mr. Wang " "Well, I forget _______ I was supposed to go to."
I don't doubt ________ he'll come.
Why the explosion occurred was ____the laboratory attendant had been careless.
They came to the conclusion ________ by a computer.