A serious study of physics is impossible ________ some knowledge of mathematics.
—Why is your wife wearing a mask in such good spring? —Because she is_________ to flowers.
The old gentleman is considering _________he will move to New York with his daughter and son-in-law or live alone at home.
The police are looking for the witnesses,__________ words will make a difference to the victim.
—You seem familiar with Mr. John? —Of course, we________ together for three years in the 1990s. have worked B. had workedC. are working D. worked
As a girl, it’s important to know what colours look good___________your skin.