6. (北京卷)设，则等于 　　　　　．

5．(2008陕西文、理)已知是等差数列，，，则该数列前10项和等于 　　　　　　　．

4．(2008全国Ⅰ卷理)已知等差数列满足，，则它的前10项的和 　　　　　　

3．(2008年电白测试卷 ) 三个实数a、b、c成等比数列，若a+b+c=1成立，则b取值范围是　　　　　　 ．

2.(2008江苏卷11)已知，，则的最小值 　　　　．

1.(2008江西卷改编)若函数的值域是，则函数的值域是　　　　 .

10.(★★★★★)Of the two toys,the child chose________.

　　 A.the less expensive one B.the one most expensive

　　 C.the least expensive D.the most expensive of them

9.(★★★★)Mr.Smith has to travel more often than________ in his history.

　　 A.else anyone B.anyone

　　 C.anyone else D.nobody else

8.(★★★★★)It is a mistake to think that the earth is a bit________ from the sun in winter.

　　 A.closer B.near

　　 C.far D.farther

7.(★★★★★)How beautiful she sings!I have never heard________.

　　 A.the better voice B.a good voice

　　 C.the best voice D.a better voice