社会学的研究对象是（） ["社会结构","社会运行","社会制度","社会整体结构及其运行规律"]
异形胞是（）中的较为特殊的一种细胞，仅在其中的一些丝状藻中存在。 ["隐藻门","硅藻门","绿藻门","蓝藻门"]
What is the result？（） ["peep","bark","meow","Compilation fails.","An exception is thrown at runtime."]
高聚物改性沥青防水卷材（），上下层卷材不得相互垂直铺贴。 ["宜平行屋脊铺贴","应垂直屋脊铺贴","可平行或垂直屋脊铺贴","宜与屋脊成45°方向铺贴"]
What are three factors that limit the maximum distance of an amplified optical signal without regeneration？ （） [" fiber dispersion"," signal attenuation"," transmitter power"," amplifier bandwidth"," receiver dispersion tolerance"]
整流发电机上的二极管具有（）。
