上颌牙列中牙周膜的排列顺序正确的是（）
A.76543
B.67345
C.67435
D.76345
E.67354
参考答案：B
"I don't think it's my _____ that the TV blew up. I just turned it on, that's all," said the boy. [ ]
A. error
B. mistake
C. fault
D. duty
已知x1是方程x+lgx=3的根，x2是方程x+10x=3的根，则x1+x2值为______．
