20．No decision　　　 　about the holding of the conference until all the related factors have been taken into consideration．

　　　 A．will be made　 　　　　　　　　　　　　　　　 B．is made　 　　　 C．has been made 　 D．is being made

19．I've always been very　　　　 　about giving my address to strangers．

　　　 A．familiar　 　　　　 B．excited　 　　　　　 C．cautious　　 　　 D．concerned

18．If you let challenges and difficulties benefit　　　　 　depress you, much more can be accomplished than you thought possible．

　　　 A．more than 　　　 B．rather than　 　 C．less than 　　　　 D．other than