Definition: to relax when you should be careful or ready to deal with something Level: C2
即使身处朋友之中，他也从不放松警惕。
He never ___lets ___his ___guard ___down, even when among friends.
史蒂文斯总是很谨慎，从不放松警惕。
Stevens is always cautious and never ___lets ___his ___guard ___down.
在谈判中，我一刻也不能放松警惕。
In negotiations, I can't afford to ___let ___my ___guard ___down for a moment.
