A. R=(tR1-tR2)(W1/2+W2/2) B. R=(tR2-tR1)(W1/2+W2/2) C. R=(tR2-tR1)W0.05h D. R=2(tR2-tR1)(W1+W2) E. R=5.54(tR/Wh/2)
A. 正确 B. 错误