表达 “lose one’s nerve” 的意思是 “屈服于恐惧和焦虑，失去了做某件事情的勇气，惊慌失措”。人们常常用这个表达来劝他人 “别害怕”：“Don’t lose your nerve.”。

例句
Sarah really lost her nerve when she had to speak in front of a big crowd. She was sick afterwards.
当莎拉不得不在一大群人前讲话时，她变得惊慌失措。之后她身体很不舒服。

The footballer didn’t lose her nerve as she scored the penalty.
那名足球运动员在射点球时沉着应战，一脚破网。

Just relax – don’t lose your nerve – you’ll pass the exam.
放松点，别慌张，你会通过考试的。