在四边形ABCD中,对角线AC与BD交于点O,△ABO≌△CDO.(1)求证:四边形ABCD为平行四边形;(2)若∠ABO=∠DCO,求证:四边形ABCD为矩形.
请你用英语描述你同桌的衣着。
This is ……. He/ She……. Her/ His name is……. She/ He is……years old. Look, he's/she's is wearing…….
实验室测定某铝样中铝的含量时,取6g含杂质的铝样(杂质不溶于水也不与酸反应)加入到300g稀盐酸中,恰好完全反应,过滤得滤液304.8g,则该铝样中铝的质量分数为( )