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问题
选择题
设a=-1×(1-2)-3,b=-1-(2-3),c=-[(-1)-(-2)-3],则-a-[-b-(-c)]=( )
A.1
B.0
C.-1
D.-2
答案
答案:
B
填空题
若数列{a
n
}(n∈N
+
)为等差数列,则数列
b
n
=
a
1
+
a
2
+
a
3
+…+
a
n
n
(n∈
N
+
)
也为等差数列,类比上述性质,相应地,若数列{c
n
}是等比数列且c
n
>0(n∈N
+
),则有数列d
n
=______(n∈N
+
)也是等比数列.
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选择题
—______does she do on weekends?
—She watches TV.
A. What
B. Where
C. Who
D. How
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