since all the information is in the current price, you don't have to worry about whether it went up or down yesterday, to decide what it's going to do today.

因为当前价格代表了所有信息，你就不需要去考虑昨天股价,是涨了还是跌了，再去判断它今天的价格会怎么变化。

麻省理工公开课 - 计算机科学及编程导论课程节选

Whether they're more inefficient when things are going up or when things are going down.

是不是在事情进展顺利或受阻的时候,市场会更没有效率。

耶鲁公开课 - 金融市场课程节选