老年人钙的吸收率为()。 A.10% B.20% C.30% D.40%

题型:单项选择题

问题:

老年人钙的吸收率为()。

A.10%

B.20%

C.30%

D.40%

考点:公共营养师营养师基础知识公共营养师基础知识
题型:单项选择题

我国在南极地区的两个科学考察站—长城站和中山站,建设时间选在2月份的主要原因是[ ]

A.是暖季,气温高    

B.是暖季,降水多

C.是冬季,气温高    

D.是冬季,降水多

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叶绿素是绿叶进行光合作用的主要场所。                            (    )

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在深厚软黏土地基上修建路堤,采用土工格栅加筋土地基,下列说法中错误的是 ( )。

A.采用加筋土地基可有效提高地基的稳定性

B.采用加筋土地基可有效扩散应力,减小地基中的附加应力

C.采用加筋土地基可有效减小工后沉降量

D.采用加筋土地基可有效减小施工期沉降量

题型:单项选择题

Many people are surprised when they find the Internet(因特网)was set up in the 1960s. At that time, computers were large and expensive. Computer networks(网络) didn’t work well. If one computer in the network broke down, then the whole network stopped. So a new network system (系统) had to be set up. It should be good enough to be used by many different computers. If a part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time.
At first the Internet was only used by the government, but in the early 1970s,universities(大学) ,hospitals and banks were allowed(允许) to use it too. However, computers were still very expensive and the Internet was difficult to use. By the start of the 1990s, computers became cheaper and easier to use.
Today it is easy to get on-line(上网) and it is said that millions of people use the Internet every day. Sending e-mail is more and more popular among students.
The Internet has now become one of the most important parts of people’s life.

The word" information" may probably mean

A. letter


B. message

C. number

题型:单项选择题

配制0.5%过氧乙酸2000ml,需2%过氧乙酸()

A.100ml

B.200m1

C.300ml

D.400ml

E.500ml

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