架空燃气管道与人行道的垂直净距离不小于（）米。
A.1.9
B.2
C.2.1
D.2.2
参考答案：D
标有“6V 6W”、“6V 1.5W”字样的灯L1和L2串联在某电源上设灯丝的电阻不变，则通过灯的电流之比是 ______，实际功率之比是 ______，要保持亮灯安全工作，电源电压不应超过 ______V．
Jenny was looking for a seat when, luckily, a man _____ and left.[ ]
A. took up
B. got up
C. shut up
D. set up
