直角三角形中两锐角平分线所交成的角的度数是[ ]
A.45°
B.135°
C.45°或135°
D.都不对
答案:C
A.20s
B.40s
C.50s
D.60s
人们吃进去的食物和吸入的空气都要通过咽.______.(判断对错)