在等差数列{an}中,a3+a6+3a7=20,则2a7―a8的值为_________.
4
题目分析:等差数列性质:若则,所以因此
Do you want to know __________ my school?[ ]
A. on
B. about
C. from
D. at
水丸的黏合剂是
A.黄酒、醋、稀药汁等
B.蜂蜜
C.蜜水
D.药材提取液浓缩成膏
E.蜂蜡