问题
选择题
—Fire is very useful to human!
—Yes, especially in winter a fire _____________warm.
A．used to keep
B．can be used to keep
C．is used to keeping
D．was used to keeping
答案
答案：B
考查固定用法。used to do，过去常常，现在已不再如此；be used to do sth.被用于做某事；be used to doing sth.习惯于做某事。根据句意，应是火被用来取暖。所以选B。