以防;以防万一;如果;假如
牛津电影里 70%
以防;以防万一
because of the possibility of sth happening
编辑释义电影里 30%
如果;假如
if; in the event that (a condition, not a precaution taken beforehand)
释义来自《牛津高阶英汉双解词典》第 9 版