根据句意，用括号内所给单词的适当形式填空。

1. I got the pen on my ________ (twelve) birthday.

2. Parents should teach their children to make decisions by ________ (they).

3. There are many little ________ (collect) in our class.

4. He was so tired that he fell fast _________ (sleep).

5. We must be careful when we _________ (across) the road.

城市道路衔接的原则，正确的是()。

A．次要让主要

B．低速让高速

C．交通性让生活性

D．新建的让已建的

E．适当分离