在等差数列{an}中,已知|a3|=|a9|,公差d<0,则使其前n项和Sn取得

题型:选择题

问题:

在等差数列{an}中,已知|a3|=|a9|,公差d<0,则使其前n项和Sn取得最大值的自然数n是[ ]

A.4或5

B.5或6

C.6或7

D.不存在

考点:等差数列的前n项和
题型:选择题

关于关节腔的描述,错误的是()

A.含有少量的滑液

B.关节腔内为负压

C.负压有维持关节稳固的作用

D.腔内没有其他结构

E.是关节的基本构成之一

题型:选择题

(三)

The Erie Canal was the first important national waterway built in the US. It crossed New York from Buffalo on Lake Erie Troy to Albany on the Hudson River. It joined the Great Lakes with the Atlantic Ocean. The canal served as a route over which industrial goods could flow into the west, and materials could pour into the east. The Erie Canal helped New York develop into the nation’s largest city.

The building of the canal was paid for entirely by the state of New York. It cost $ 7 143 789, but it soon gained its price many times over. Between 1825, when the canal was opened, and 1882, when toll charges were stopped, the state collected $121 461 891.

For a hundred years before the Erie was built, people had been talking about a canal which could join the Great Lakes and the Atlantic Ocean. The man who planned the Erie Canal and carried the plan through was De Witt Clinton. Those who were against the canal laughingly called it "Clinton’s Ditch". Clinton talked and wrote about the canal and drew up plans for it. He and Governor Morris went to Washington in 1812 to ask for help for the canal, but they were unsuccessful.

Clinton became governor of New York in 1817, and shortly afterwards, on July 4, 1817, broke ground for the canal in Rome, N. Y. The first part of the canal was completed in 1820. As the canal grew, towns along its course developed fast. The length of the canal is 363 miles.

Which of the following is true according to the passage()

A.Clinton broke ground for the canal at both ends.

B.Clinton started building the canal before he became governor.

C.All parts of the canal were completed at the same time.

D.Construction of the canal took eight years.

题型:选择题

支票出票人的主要票据义务是()。

A.直接付款义务

B.担保义务

C.背书义务

D.承兑义务

题型:选择题

三级资质等级物业服务企业的注册资本为( )万元人民币以上。

A.10
B.20
C.30
D.50

题型:选择题

结合教学实践,分析学生学习动机的培养和激发。

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