I regret ________ that you have failed the exam, but what you should do now is not to regret ______ so much time but to seize every moment from now on.
Your understanding on the theory is________satisfactory. You must read more after class.
Not until they left school________ how much their teachers loved them and helped them.
I thought Peter would have helped you.________is a great pity that he should be so selfish.
We have to________new customers to our restaurant by providing the best service at the lowest price.
-Do you want to go out tonight? -I'm easy.________.