讲解文本：
cold feet 胆怯，打退堂鼓，信心或勇气的丧失 He planned to talk to Mary, but then he got cold feet. 他本打算去跟Mary说话，但后来临阵退缩了。 This is not the time to get cold feet. Let's do it! 现在不是打退堂鼓的时候，行动吧！
疯狂练习吧！
