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27.Can you still remember the farm      we enjoyed plenty of fresh fruit half a year ago?

    A.that           B.when         C.where          D.what

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26.-What happened to the ancient town?

    -      .

    A.It destroyed in the flood            B.The flood was destroying it

    C.The flood was destroyed it          D.It was destroyed in the flood

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25.-Your grandfather is always full of    .What’s the secret?

    -Playing Taiji every morning.

    A.taste           B.energy        C.relief           D.credit

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24.--- I am always feeling nervous before an exam.

   ---     .Do believe your hard work will surely pay off.

    A.Take your time                   B.Take a good rest

    C.Take it easy                     D.Take your turn

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23.Although you have traveled to many scenic spots before,    of them are as attractive as the one I visited this summer vacation.

    A.any           B.none          C.neither         D.all

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22.--- I am sorry to have    much of your spare time.

   --- That’s OK, and I am glad to help you.

    A.taken up        B.taken on        C.taken off       D.taken in

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第一节:单项填空(共15小题,每小题1分,满分15分)

从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

21.    moment he saw Zhao Benshan’s funny performances, he burs into    laughter.

    A.A;不填        B.A;the         C.The;不填       D.The; a

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12.(16分)设数列{an}的前n项和为Sn

已知a1=1,2Sn=(n+1)an(n∈N*).

(1)求a2a3a4的值;

(2)写出从an1an的递推公式;

(3)求数列{an}的通项公式.

[解析] (1)由2(1+a2)=3a2,得a2=2.

由2(1+2+a3)=4a3,得a3=3.

由2(1+2+3+a4)=5a4,得a4=4.

(2)∵2Sn=(n+1)an(n∈N*),

∴2Sn1nan1(n>1),

两式相减,得2an=(n+1)annan1

∴递推公式为anan1(n>1).

(3)由(2)得anan1

=·an2

=··an3

……

=···…··a1na1.

又∵a1=1,

∴数列{an}的通项公式为ann(n∈N*).

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