如何理解先行词为case ,situation ,point等的定语从句,引导词用where

如何理解先行词为case ,situation ,point等的定语从句,引导词用where如:We will discuss a number of cases ( ) beginners of English fail to use the language preperly.A.which B.as C.why D.where2.He was driving so fast as to get himself into a dangerous situation ( )he is likely to lose the control over his car.A.which B.as C.why D.where两道题都选where ,但是case,situation都不是地点,如何理解要选用where?thanks!