拖拉机的履带由一块块金属板连接而成，每块板上都有1-2条凸起的棱，金属板的作用是_______，棱的作用是________。
增大受力面积减小压强；增大摩擦
The nurse is caring for a 45-year-old male client admitted with a retinal detachment in his left eye. What symptoms would the nurse expect to find during assessment
A. Flashing lights in the visual field.B. Sudden eye pain.C. Loss of color vision.D. Colored halos around lights.
患者缺失，义齿设计：基牙，弯制卡环，塑料基托连接，义齿蜡型采用混装法装盒
该义齿牙托的用量为（）
A.0.5ml
B.1～1.5ml
C.2ml
D.3ml
E.4ml
缺失，义齿设计：基牙
，弯制卡环，塑料基托连接，义齿蜡型采用混装法装盒