The bus hit against a tree in the fog and __________to the deep valley, with ten passengers killed and twenty wounded.
A．down did it roll B．down rolled it C．down it rolled D．it down rolled
Understanding the cultural habits of another nation, especially ____________ containing as many different subcultures as the United States, is very difficult.
A．one B．that C．some D．the one
As we all know, apples are sold by ____ weight, and socks are sold by _______dozen.
A．the; a B．/; a C．/; the D．the; the
Many difficulties have ______ as a result of the changeover to a new type of fuel.
A．risen B．arisen C．raised D．arose
——Why are the tax collectors so busy?
——Many people prefer to have their tax forms completed by a professional rather than ___.
A．do it themselves B．doing it themselves
C．to do it themselves D．done by themselves
It was in the small house _______ was built with stone by his father _______ he spent his childhood.
A．which , that B．that , which C．which , which D．that ,where
