原题如下：
Sales of roof material, by quarter, since 2002 for Carolina Home Construction, Inc. are shown as following

Year	Quarter	sales
2002	1	210
	2	180
	3	60
	4	246
2003	1	214
	2	216
	3	82
	4	230
2004	1	246
	2	228
	3	91
	4	280
2005	1	258
	2	250
	3	113
	4	298
2006	1	279
	2	267
	3	116
	4	304
2007	1	302
	2	290
	3	114
	4	310
2008	1	321
	2	291
	3	120
	4	320

数据有些乱，附件里再放一份
A.Determine the typical seasonal patterns for sales using the ratio-to-moving-average method.
B.Depersonalizes the data and determine the trend equation.
C.Project the sales for 2009,and then seasonally adjust each quarter.
不知道这道题本身是否表述欠妥，如题目没问题，还请达人对B.C两问如何理解及操作给一些提示，不胜感激