safety意为保险机、中卫时，是可数名词
a safety (catch) （枪，炮的）保险机
a safety (美式足球) 中卫
意为安全、保险时，是不可数名词
Production has been suspended while safety checks are carried out.
在进行安全检查期间生产暂停。
He didn't seem in the least concerned for her safety.
对她的安全他似乎一点都不担心。
Firefighters formed a human chain to carry the children to safety.
消防队员组成人链把孩子们救到了安全的地方。
温馨提示：
