龋病二级预防的内容包括（）
A.定期口腔检查
B.X线辅助诊断
C.窝沟封闭
D.早期诊断
E.早期预防
参考答案：A, B, D
视觉空间是指哪些空间（）
A、DP
B、VP
C、PP
D、IP
Directions:
Write an essay of 160 -200 words based on the following drawing. In your essay, you should first describe the drawing, interpret its meaning, and state your own opinion on it.
You should write neatly on ANSW. ER SHEET 2. (20 points)
