One of the real services of the historical novel is not that it can be a substitute for history, but that it can be a(n) extension.（）

单项选择题To impose computer technology () teachers is to create an environment that is not conducive to learning.

A. with
B. to
C. in
D. on

单项选择题From 1965 to 1978 American consumer prices increased at an average annual rate of 5.7 percent. This ominous shift was followed by consumer price gains of 13.3 percent in 1979.（）

A. promising
B. overwhelming
C. threatening
D. astonishing