20. It is only in the last sixty years that　　　　 any evidence that Loch Ness Monster might exist.

A．there has been　 　　 B．there was　　 　　　 C．it has been　　　 　　　　 D．it had

19.________all his courage, he invites Celine to get off the train with him．

A．To gather　 　 　　　B．Gathered　 　　　 　C．Gathering 　　　 　　　　D．Being gathered

18. _______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

17. Young people go to college with the expectation that ____________ educated people get a higher pay.

A．good　　　　　　 B．better　　　　　　 C．best　　　　　　　　　 D．the best