Investors have a bad record of calling market tops and market bottoms .
投资者预测市场顶部和市场底部的历史记录很差。
Many hollows have smooth , flat bottoms and feature highly reflective material .
许多空洞拥有光滑平坦的底部，显示出高反射率材料的特点。
Exclusively sulfide-eating bacteria coat the bottoms of the rocks in a white biofilm .
所有硫化物吃掉包裹在石块底部的细菌形成白色的生物膜。
You can also prevent mildew from forming on the bottoms of rugs and carpeting by misting the backs with full-strength white vinegar from a spray bottle .
您也可以用喷壶在垫毯和地毯的背面喷上一层白醋原液，来预防地毯底部生成霉渍。
This is very rare : the last two times such events happened so close together were in july 2006 and november 1987 , which both turned out to be significant market bottoms .
