螺纹接口常用的密封材料是()A、铝油 B、油麻 C、聚四氟乙烯

题型:单项选择题

问题:

螺纹接口常用的密封材料是()

A、铝油

B、油麻

C、聚四氟乙烯

考点:燃气具安装维修工考试燃气具安装维修工考试题库
题型:单项选择题

In 1998 consumers could purchase virtually anything over the Internet. Books, compact discs, and even stocks were (1) from World Wide Websites that seemed to (2) almost daily a few years earlier, some people had predicted that consuners accustomed to shopping in stores would be (3) to buy things that they could not see or touch (4) . For a growing number of time-starved consumers, however, shopping from their home computer was proving to be a convenient (5) to driving to the store.

A research estimated that in 1998 US consumers could purchase $ 7.3 billion of goods over the Internet, double the 1997 total. Finding a bargain was getting easier, (6) the rise of online auctions and Websites that did comparison shopping on the Internet for the best (7) .

For all the consumer interest, (8) in eyberspaee was still a largely (9) business, however. Internet pioneer Amazon. eom, which began selling books in 1995 and later (10) into recorded music and videos, posted (11) of $ 153.7 million in the third quarter, up from $ 37.9 million in the same period of 1997. Overall, (12) , the company’ s loss widened to $ 45.2 million from $9.6 million, and analysts did not expect the company to turn a profit (13) 2001. (14) the great loss, Amazon. tom had a stock market value of many billions, reflecting investors’ (15) about the future of the industry.

Internet retailing appealed (16) investors because it provided an efficient means for reaching millions of consumers without having the cost of operating (17) stores with their armies of salespeople. Selling online carried its own risks, however, (18) so many companies competing tor consumers’ attention, price competition was (19) and profit (20) thin or nonexistent.

18()

A.for

B.despite

C.to

D.with

题型:单项选择题
已知函数f(x)=Asin(ωx+ψ)+B(A>0,0<ω<2,|ψ|<
π
2
)
的一系列对应值如下表
x-
π
6
π
3
6
3
11π
6
3
17π
6
y-1131-113
(1)根据表格提供的数据求函数y=f(x)的解析式;
(2)求函数y=f(x)的单调递增区间.
题型:单项选择题
一根蜡烛在凸透镜下成一实像,物距u,像距v和凸透镜的焦距f满足关系式:
1
u
+
1
v
=
1
f
.若f=6厘米,v=8厘米,则物距u= 厘米.
题型:单项选择题

配送中心是指商品集中出货、保管、包装、加工、分类、标付价格标签、装货、配送的场所或()。

A.基地

B.经营主体

C.批发商

D.车站

题型:单项选择题

会计在月末结账前发现所填制的记账凭证无误,但根据记账凭证登记账簿时,将1396元误记为1369元,按照有关规定,他应采用的错账更正方法是( )。

A.画线更正法
B.红字更正法
C.补充登记法
D.平行登记法

更多题库