〔R135〕 A coffee cup and a water glass were both set running on a road.  A car came honking warningly.  The coffee cup heard the car and shunned it in time.  But the water glass could not hear the car and was run over.  Why could one hear the car but not the other?

〔譯註〕 一個咖啡杯和一個盛水杯兩個都被弄得在路上跑。一輛車子過來，警告地按喇叭。那咖啡杯聽到車子而及時避開它。可是那盛水杯無法聽到車子而被輾過去。為何一個聽得到車子，另一個則不能？              

註：1. honk: 車子 (按喇叭) 發出如雁叫般的聲音。

2. shun: 躲開，規避掉。

〔提問〕 If the reason was that the coffee cup had something which the water glass did not have, what then was the something?

 〔謎底〕  an e__