15. I haven’t tidied my office ___. a just b already c yet d since
16. I can sing, but not as ___ as my sister.
a well b good c best d better
17. That’s my money! Give ___!
a back b it back c back it d it
18. Richard isn’t very good ___.
a to dance b at dancing c dancing d dance
19. I’m sure Canada isn’t as big ___ Russia.
a as b than c to d like
20. It’s important ___ too much alcohol.
a not to drinking b not to drink
c not drink d not drinks
