lostandfound;失而复得
trytosavealittleonlytolosealot;因小失大
letslipagoodopportunity;loseagoodchance坐失良机
begreatlydisappointed大失所望
turnpale失色
breakone'spromise失信
haveaslipofthehand;dropaccidentally;losehold(of)失手
loseone'sbearings迷失方向
fearthattheremaybesomemishap;唯恐有失
Eventhewisearenotalwaysfreefromerror.;Onecan'tbetoocareful.智者千虑,必有一失