30. _____ from other continents for millions of years, Australia has many plants and animals not found in any other country in the world.

A. Being separated　　　　 B. To be separated　　

C. Having separated　　　　 D. Having been separated

29. Away _____ and in ______.　　　　

A. went he; came his sister　　 B. he went; his sister came　　

C. went he; his sister came　　 D. he went; came his sister

28. That was really a splendid evening．It's years ____ I enjoyed myself so much．

A．when　　　 B．that　　　 C. before　　　 D．since

27. ____ of the truth of the report, he told his colleagues about it.　

A. Convinced　　　　　　 B. Convincing

C. To convince　　　　　 D. Having convinced