设数列{an}的前n项和为Sn,如果a1=-5,an+1=an+2,那么S1,S2,S3,S4中最小的是[ ]
A.S1
B.S2
C.S3
D.S4
答案:C
What about _____________at home?
A.do some reading
B.to do some reading
C.doing some reading
D.doing any reading
下列不属于油脂性基质的是()
A.聚乙二醇
B.凡士林
C.石蜡
D.二甲硅油
E.羊毛脂