根据句意,用括号所给单词的适当形式完成下列句子.

根据句意,用括号所给单词的适当形式完成下列句子.
1.You and David______ able to find out the answer to the question.(be)
2.Mr Wang is the_____ of the book about the moon.(write)
3.His_____ brother is my good friend.(young)
4.We______ him three years age.(know)
5.Are they able to ______ on time?(arrive)