以防万一: make provision [provide] against emergencies; be prepared for any contingency [all contingencies]; be prepared for the worst; have a spare wheel ready all the time; have two strings to one
他握紧手抢以防万一: he gripped his pistol tightly just in case
你最好有两手准备以防万一: you'd better have two strings to your bow just in case of emergency
在现场以防万一你知道它健美: miamis on the scene just in case you didnt know itmiamis