—Where have you _________?
— I've ________ the supermarket.
A:gone, gone to
B:been, been to
C:gone, been at
D:been, gone to
为了接受汉族的先进文化,北魏时期要求采用汉姓、学说汉话的少数民族是( )
如图,等腰梯形ABCD,AD∥BC,BD平分∠ABC,∠A=120°.若梯形的周长为10,则AD的长为____
称取粗盐 →① →②BaCl2→③NaOH →④ →⑤过滤 滤液 →⑥适量盐酸 →⑦蒸发、结晶、烘干 精盐