设等比数列a_n中，每项均是正数，且a₅a₆=81，则 log₃a₁+log₃a₂+…+log₃a₁₀=（    ）.

Nowadays millions of people of all age take pleasure in a               1. _______

hobby which is both interested and fun. And every year                            2. _______

more and more people start a stamp collection of your own                   3. _______

and discover an interest which can even last lifetime. Starting               4. _______

your collection of stamps are easy became they are everywhere.         5. _______

Holiday and birthday postcards from relatives and letters                       6. _______

from friends can all provide you for stamps from all over                        7. _______

the world. So once you’ve started collecting seriously, you                      8. _______

will probably want to join in the Stamp Collectors’ Club                           9. _______

which exist to add more stamps to your collection.                                    10. _______