A:would be freezing cold
B:would be frozen cold
C:would be freezing coldly
D:can freeze coldly
按要求填空:
为使教室内的学生免受环境噪声的干扰,下列哪种方法是最合理的?( )
如图,在Rt△ABC中,∠A=90°,∠ABC=2∠C,BD=CD.求证:CD=2AD.