题目

High-speed trains travel at 300 kilometers an hour，which is about    normal trains.   A.four times the speed as                      B.the speed four times of   C.four times as the speed of                   D.four times the speed of   答案：D 下列含脂肪成分较多的食物是（　　）A．鱼B．小麦C．蜂蜜D．肥肉