根据所给汉语及句意，以适当的形式填写正确的单词。

1．The dictionary are on the        （地板）．

2．Is the        （植物）on the table?

3．       （十九）and one is twenty．‘

4．That book is very        （有趣的）．

5．The question is        （困难的）for me to answer．