根据句意，写出已给了首字母的单词。

1．She talks less in front of lots of people．He is t          of speaking in public．

2．--How many people are there in the world now?

--About 6.4 billions．The population of the world is i        very fast．

3．The girl is shy．She stands with her back t         us．

4．--The new tea produces a p          smell．Would you like to drink some?

    --Yes．Just a little．

5．One c         means a period of one hundred years．