If you get cold feet or have cold feet about something you have planned to do， you become nervous about it and not sure that you want to do it.

　　如果你对某个你计划要做的事get cold feet或者是have cold feet，就表示你对你计划要做的这个事感到胆怯、紧张，不确定你是否想做它。

　　I had agreed to give a speech， but as the time approached， I began to get cold feet.

　　我已经答应进行一次演说，但随着时间的逼近，我开始胆怯了。

　　A：I’m scared。 I’m not sure I want to go through with it.

　　A：我害怕。我不确定自己想不想去了。

　　B：We didn’t drive all the way down here for that piece of paper for you to get cold feet at the last second.

　　B：我们开了这么远的路来拿证明，可不是为了让你临阵脱逃的。