管道的阻力与管道的长度成正比；与水流速度的平方成正比；与管道的直径成正比。
参考答案：错
不锈钢加热时，应保持板坯在炉内（）。
— Do you know ________ the 2011 Xiamen International Marathon was held?
— On January 2.[ ]
A. when it was that
B. when was it that
C. what it was that
D. what was it that
