下列哪一项是AIDS的主要传播途径？（）
A.血液及其制品传播
B.性接触传播
C.吸毒传播
D.经胎盘传播
E.产道内感染传播给新生儿
参考答案：B
While the government says there is a(n) ______ supply of houses, prices of apartments have been going up these years.
A．parallel
B．absent
C．abundant
D．short
二类防雷建筑物(防止直击雷)接地冲击电阻最大允许值为10Ω。( )
