英语语法分析

But they did make one avoidable mistake that led directly to their overoptimism.

但是他们的确犯了一个能够避免的错误，这个错误直接引导他们过于乐观。

In equities, the widespread sell-off may have been a reaction to the overoptimism that prevailed earlier this year.

而随处可见的股票抛售行为可能是年初过度乐观派人士的反应。