根据句子意思，用括号中所给单词的适当形式填空。
Don’t be so            (patient)! The bus will be here soon.
He has become a famous doctor in his            (twenty).
The little girl had no choice but            (ask) for mother’s help.
Sarah had her washing machine            (repair) yesterday, but it doesn’t work now.
Millie often doubts whether it is worth _____________ (work) so hard.