A:①②
B:①③
C:②③
D:①②③
等差数列{an}中,a1+a4+a7=39,a3+a5+a9=27,则前9项的和S9=( )
下列叙述不正确的是( )
— Which do you prefer, coffee or cola?
— ________, thanks. I'd like a cup of tea.