20번. 다음 글의 흐름으로 보아, 이어질 글의 순서로 가장 적절한 것을 고르시오. (원문 변형 O) If we look at human history, it’s clear that the ability to react to possible danger has helped us survive. So, it's not strange that we tend to feel anxious in uncertain situations. (A) Think about how often you've spent sleepless nights fearing something terrible that, in the end, never even happened. And even if that fear came true, wor..