叙述并指出颊车、通里、内庭的定位
参考答案:
颊车:下颌骨前上方一横指凹陷中,咀嚼时咬肌隆起最高点处
通里:腕横纹上1寸,尺侧腕屈肌腱的桡侧。
内庭:足背第二、三趾间缝纹端。
The problem is too difficult for him. He _______ solve it by himself without any help.
A.can't
B.mustn't
C.shouldn't
D.needn't
防止动力性下降的措施?