________ is known to everyone, the moon travels around the earth once every month.
When he was there, he ________ go to that coffee shop at the corner after work every day.
—Do you still remember when we went to Nanjing? —I can't remember now but ________ sometime last summer?
Had I known about this computer program, a huge amount of time and energy ________.
If he ________ my advice, he wouldn't have lost his job.
Bob would have helped us yesterday, but he ________.