艾滋病的传播途径是什么?
参考答案:HIV传播途径主要有3种:
一是性接触传播;
二是血液传播,包括输血、注射、吸毒、血制品及外伤;
三是母婴传播。
计算[(x-2y)2+(x-2y)(x+2y)+2x(2x-y)]÷2x.
A luxury express train jumped the tracks on a bridge in eastern India, killing at least 50 on the spot. According to the Northern Railway spokesman, the death () is expected to rise.
A. figure
B. toll
C. span
D. yield