Things have changed a lot ____ I wrote to you last time.
The bus hit against a tree in the fog and __________to the deep valley, with ten passengers killed and twenty wounded.
Understanding the cultural habits of another nation, especially ____________ containing as many different subcultures as the United States, is very difficult.
As we all know, apples are sold by ____ weight, and socks are sold by _______dozen.
Many difficulties have ______ as a result of the changeover to a new type of fuel.
——Why are the tax collectors so busy?——Many people prefer to have their tax forms completed by a professional rather than ___.