问题
选择题
在等差数列{an}中，公差为
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答案
由等差数列的性质可得 a2+a4+a6+…+a100 =a1+a3+a5+…+a99 +50d=60+50×
=85，1 2
故选D．
搜题请搜索小程序“爱下问搜题”
在等差数列{an}中，公差为
|
由等差数列的性质可得 a2+a4+a6+…+a100 =a1+a3+a5+…+a99 +50d=60+50×
=85，1 2
故选D．
Have you got any wonderful plans for your coming winter vacation? Here are some wonderful films for you to kill time.
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With a baby on his way, a young couple, Burt and Verona, look at their lives and are puzzled about what they really want. So they hit the road and seek a place to call home. On their journey, they visit a handful of characters and learned a lot. 
Easther, a bright and well-behaved child, however, is not as innocent as she appears. Soon after being taken home, the peace of her adoptive family is completely changed…
Tom is in love with Summer from the moment he sees her. Can he accept that she simply likes him for now, not for forever? The movie is about Tom wrestling with that reality. Tom remembers his love, Summer, as a series of joys and bafflements(阻碍,迷惑). But Summer is just herself and he cannot have her. 
The director Roland Emmerich successfully dresses a corny story with an old Mayan prediction, which is believed by many to happen in the coming 2012 and as a result, attracts millions of people into the cinema.