I know I should _____ on fat, but knowing such things is not much help when it comes to shopping and eating.
--- Will you waste your time and money on that? --- Certainly ________.
Although ________ to stop, he kept on working.
He said _____ his sister had passed the college entrance examination, and _____ she would go to college in about 20 days.
We will have a meeting next week, but we don’t know _____.
_____ for your brother, I would not have gone to see Mr. Wang.