从方框中选用合适的词并用其适当形式填空。

---Do you know the _______ of the tree? 
---It is 4 metres high.
Your idea is not good,and his is even_______.
Ning Zetao is one of the most popular              in China.
He finishes the ________ homework of us three.
My mum often tells me to speak to the old_________.