There snow in December.
A:is
B:are
C:have
澳门的主要经济支柱是( )
——Your father was worried about something this morning. Why?——He wondered .
看图写词语的音节。
____ ____ ____ ____
如图,⊙O的半径为6,线段AB与⊙相交于点C、D,AC=4,∠BOD=∠A,OB与⊙O相交于点.
(1)求BD长;
(2)当CE⊥OD时,求证:AO=AD.