{an}为等比数列，a1+a2+a3=1，a2+a3+a4=2，那么a3+a4+a5=（ ）。
4
Aunt Mary is crazy about shopping. She must be snapping up the bargains in the department store during
such a sale, _____? [ ]
A. mustn't she?
B. isn't she
C. needn't she
D. doesn't she
电解液的比重是指在环境温度20℃时，若电解液温度不在20℃，其比重应按温度每升高或降低1℃，比重增加或减少（）。
A.0.07
B.0.007
C.0.0007
D.0.7
