— ?
— I went to the beach.
A:What did she do last night.
B:Where did you go on vacation
C:Did you go to the park
D:Did he go to the beach
葡萄糖经小肠黏膜上皮进入毛细血管,需透过的磷脂分子层数是( )
(Ⅰ)求数列{an}的通项公式
(Ⅱ)设bn=n•2 an 求数列bn}的前n项和Sn.
唐宋时期,众多诗词作品得以刊印成集,主要得益于( )