将下列单词按其所属类别归类。

schoolbag, foot, blond, hand, red, China, cap, orange, Cuba, dress,

eraser, ear, England, shirt, ruler, Japan, shoe, head, black, pencil.

1. 学习用品:                                                                                      

2. 身体部位:                                                                                      

3. 颜色名称:                                                                                      

4. 国家名称:                                                                                      

5. 服装名称:                                                                                      

患者女，66岁，双侧游离缺失，基牙，探（-），叩（-），余无异常。医生为其设计近中隙卡，RPI卡环，舌杆连接

加强带的主要作用是（）

A.防止义齿下沉

B.防止支架折断

C.防止义齿翘动

D.增加义齿固位

E.减少义齿受力时对基牙的损害