看图填空，一空一词。

1. What can you see in the picture?

    We can see that a school ______ ______ a skating Marathon.

2. How many people are there in the picture? And who are they?

    There are seven. Five are students and the ______ of them are ______.

3. What are the they doing?

    A man and a woman are ______ Alison, most students are skating and two of them

    are ______ on the ground.

4. What is Alison doing?

    He is ______ the woman's ______.

5. When did Alison started skating?

    He started skating ______ hours ______.

塑料全冠的特点( )

A．修复体与牙体完全密合
B．修复体的轴壁不能与牙体完全密合
C．修复体邻面接触点不能密合
D．修复体强度较差
E．修复体能恢复良好的天然牙