根据所给单词的适当形式填空。

1．Things went from bad to worse. The longer people waited for help，the ___the situation became．(danger)

2．A large amount of research ________ to understand sleep recently ．(do)

3．The old dresser needs ____ again．(paint)．

4．He has some problems _____ up the plan．(make)

5．Teenagers should ____ to choose their own friends．(allow)