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 .

这种情况非常罕见：上两次此类情况发生时间非常接近是在2006年7月份和1987年11月份，最终事实表明这两次都是重要的市场底部。