A:汉与匈奴和亲
B:文成公主出嫁
C:实行改土归流
D:设立驻藏大臣
下列各组词语中没有错别字的一项是( )
213 = 4() 15 = 4() 1230 = 4()
设等比数列{an}的前n项和为Sn,若a1=1,a4=﹣8,则S5等于( )
一 Have you counted the money yet?
— No. I've just put it in an envelop.