10元8角=____元 218米=____千米
3.2米=____米____厘米
公转就是地球围绕着____转动,公转的方向是____;公转一周的时间是____。
(Ⅰ) 求c,an;
(Ⅱ) 若 bn=an2n ,求数列{bn}前n项和Tn.
-- What present do you want to buy for your father?
-- _____ . They can keep his hands warm in winter.