下列说法中,正确的有( )个.①单项式-2x2y5的系数是-2,次数是3②单项式

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问题:

下列说法中,正确的有(  )个.
①单项式-
2x2y
5
的系数是-2
,次数是3
②单项式a的系数为0,次数是1
③24ab2c的系数是2,次数为8
④一个n次多项式(n为正整数),它的每一项的次数都不大于n.
A.1B.2C.3D.4
考点:单项式
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冬季,某居民在自家较封闭房间内的一盆煤火旁发生昏迷,皮肤黏膜呈樱桃红色,导致该症状最可能的空气污染物为()

 

A.CO

B.CO2

C.SO2

D.NOx

E.PAH

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在油气井、站、库间的消防道路路面宽应不小于()米。

A.3.5

B.5

C.6.5

D.8

题型:选择题

改写下面这个划线的长句,使之成为几个短句,注意表意的明晰性和前后语意的连贯性;可以适当增删词语,但不得改变原意。

题型:选择题

数据库系统由数据库、硬件、软件和______四个部分组成。

题型:选择题

Who won the World Cup 1994 football game What happened at the United Nations How did the critics like the new play (1) an event takes place, newspapers are on the streets (2) the details. Wherever anything happens in the world, reporters are on the spot to (3) the news.

Newspapers have one basic (4) , to get the news as quickly as possible from its source, from those who make it to those who want to (5) it.

Radio, telegraph, television, and (6) inventions brought competition for newspaper. So did the development of magazines and other means of communication. (7) , this competition merely spurred the newspapers on. They quickly made use of the newer and faster means of communication to improve the (8) and thus the efficiency of their own operations. Today more newspapers are (9) and read than ever before. Competition also led newspapers to branch out into many other fields. Besides keeping readers (10) of the latest news, today’s newspapers (11) and influence readers about politics and other important and serious matters. Newspapers influence readers’ economic choices (12) advertising. Most newspapers depend on advertising for very (13) .

Newspapers are sold at a price that (14) even a small fraction of the cost of production. The main (15) of income for most newspapers is commercial advertising. The (16) in selling advertising depends on a newspaper’s value to advertisers. This (17) in terms of circulation. How many people read the newspaper

Circulation depends (18) on the work of the circulation department and on the services or entertainment (19) in a newspaper’s pages. But for the most part, circulation depends on a newspaper’s value to readers as a source of information (20) the community, city, county, state, nation, and world—and even outer space.

16()

A.way

B.means

C.chance

D.success

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