—Why did you leave the water running in the sink? —My goodness! I guess I ____ to turn off the tap.
Not until he failed in the last examination _________ he should have spent more time on study.
As a saying goes, the wise man knows he knows nothing, _________ the fool thinks he knows all.
We should show _________ concern for Mr. Smith, _________ eighty-year-old man near our home because now he has nobody to depend on.
Despite many worries before finishing the task, everything _________ well.
According to the traffic rules, you _________ wear the safe belt while you are driving.