37. No one has come up with a better explanation of why dinosaurs ______.
. _____ the book four times, I finally understood the author's theory.
Mike seldom asks ____ questions in class, but today he raised _____ fairly good one.
_____ the news, so far, has been good, there may be days ahead when it is bad.
. Although ________ after the Civil War, the American blacks still took no important role in the white Americans except as servants and laborers.
The European market has long been favoring a number of African and Caribbean countries, ________ former colonies of Britain or France.