原因

cause;grounds;reason
别问什么～。Don’t ask why./产生这种情况有两方面的～。Two things account for the occurrence./出于某种～for some reason;out of certain reason/由于上述～ for the above reason/由于这个～on this account/追究～find out the reason (or cause)/～和结果（因果）cause and effect/主要～main (or principal) reason;basic cause