precaution
n
~ (against sth) thing done in advance to avoid danger, prevent problems, etc 预防措施或方法
take an umbrella just as a precaution 带把伞, 有备无患
fire precautions/precautions against fire 防火措施
I took the precaution of locking everything in the safe. 我把一切东西都锁在保险箱里以防万一.