他担心如果自己放松了警惕，他的员工就会开始变得懒惰。

He's worried that if he ___lets ___his ___guard ___down, his staff will start to become lazy.

史蒂文斯非常始终如一，从不放松警惕。

Stevens is very consistent and never ___lets ___his ___guard ___down.

紧张的谈判结束后，她终于在晚餐时放松了警惕。

After the tense negotiation, she finally ___let ___her ___guard ___down over dinner.