20．　　 all kinds of difficulties，the workers have made rapid progress in the construction of the World Expo 2010 Shanghai．

　　　 A．With　 　　　　　　　 B．For　　 　　　　　　　 C．Under 　　　　　　　　 D．Beyond

19．_______of the household rubbish　　　　 recycled or reused since the new technology was applied．

　　　 A．Three-fourth; has 　　　　　　　　　　　　　　　　 B．Three-fourth; have been

　　　 C．Three-fourths; has been　　　　　　　　　　　 D．Three-fourths; have