结合本课知识及材料,谈谈你对“慎独”的理解。
如图,已知△ABC中,AB=AC,AB边上的垂直平分线DE交AC于点E,D为垂足,若∠ABE:∠EBC=2:1,则∠A=____ .
当黑龙江还是冰天雪地时,海南岛已是春耕大忙了,这是由于我国( )
David has become a young writer.
—Are these Chinese books?
—Yes, ______________.