The train is running 120 kilometres an hour. [ ]A. at a speed B. at the speedC.
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![The train is running 120 kilometres an hour. [ ]A. at a speed B. at the speedC.](/pic/43_612208.jpg)
The train is running ________ 120 kilometres an hour.[ ]A. at a speed
B. at the speed
C. at a speed of
D. on a speed of
试题答案
C