I haven't decided when __________ a holiday yet.
A:took
B:taking
C:to take
D:take
已知等差数列{an}满足:a5=5,a2+a6=8.
(1)求{an}的通项公式;
(2)若bn=2aa求数列{bn}的前n项和Sn.
“国以民为本,民以衣食为本,衣食以农桑为本”这句话是谁说的?( )
读我国西北、青藏地区图,回答: