20．-　　　　 you found out the accident which happened a month ago?

　　　 -By looking into it.

　　　 A．Was it what that　　　　　　 B．Was it how that

　　　 C．It was where that　　　　　 D．How was it that

19．Not that I’m unwilling to lend you the money , 　　　　that I have invested all my money in stocks.

　　　 A．because　　　　　 B．but　　　　　　　　　 C．however　　　　　　　　 D．since

18．About one in ten computer game players show signs of addictive behavior that 　　　have negative effects on their family, friends and school work , according to a new study.

　　　 A．should 　　　　　 B．could　　　　　　　 C．must　　　　　　　　　　　 D．would

17．A return Air China flight to Dubai from Beijing now costs as low as 2,900 yuan, which is 1,400 yuan cheaper than 　　　it was a few months ago

　　　 A．when　　　　　　　 B．that　　　　　　　　 C．which　　　　　　　　　　 D．what