中毒是指（）。
A.物理因素引起的损害
B.化学物质引起的损害
C.细菌感染经起的损害
D.放射物质引起的损害
E.药物引起的损害
参考答案：B
But for the help of my English teacher, I __________the first prize in the English Writing
Competition. [ ]
A. would not win
B. would not have won
C. would win
D. would have won
敷设导线时，套管应按套管内截面利用率计算。穿放多根绞合线的管截面利用率宜为（）。
A.25%～30%
B.30%～40%
C.40%～50%
D.50%～60%
