A:禁止放易燃物
B:禁止梳头
C:熄火加油
D:禁止吸烟
棱台不具备的性质是( )
A. B.
C. D.
阅读短文,回答问题。
Seeing the Doctor
Mum: What is the matter, my son?
Son: My head is hurting. I can't go to school.
Mum: Come with me to the doctor.
Son: The doctor! Oh, no! My head is not hurting. I can go to the school.
已知∠A=20°18′,∠B=20°15′30″,∠C=20.25°,则度数最大的是( )