It was not until the subprime loan crisis(次贷危机) ____ great damage to the American financial system that Americans ____ the severity of the situation.
We waited and waited.________ we had been looking forward to.
— Are you going to the concert tomorrow? — ___________I’m not sure whether I could finish my paper before that.
This old professor insisted that he _____energetic enough and that he _____.
The living room is clean and tidy, ________ a dining table already laid for a meal to be cooked.
Scientists say it will be five or six years ________ it is possible to test this medicine on humans.