变量泵—定量执行元件容积调速回路相比于定量泵—变量执行元件容积调速回路,其调速范围应

题型:单项选择题

问题:

变量泵—定量执行元件容积调速回路相比于定量泵—变量执行元件容积调速回路,其调速范围应()后者。

A.大于

B.小于

C.等于

D.都可以

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用数学归纳法证明命题P(n)对任何自然数正确,一般包括两个步骤;第一,建立基础,例如证明P(1)正确;第二,建立推理关系,例如证明n≥1时,如果命题P(n)正确则可以推断命题P(n+1)也正确。这种推理关系可以简写为:n≥1时P(n)→P(n+1)。

将上述数学归纳法推广到二维情况。为证明命题P(m,n)对任何自然数m与n正确,先证明P(1,1)正确,再证明推理关系()正确。

A.m≥1,n≥1时,P(m,n)→P(m+1,n+1)

B.m≥1,n≥1时,P(m,n)→P(m,n+1)以及P(m+1,n+1)

C.m≥1,n≥1时,P(m,n)→P(m+1,n)以及P(m,n+1)

D.n≥1时,P(1,n)→P(1,n+1);m≥1,n≥1时,P(m,n)→P(m+1,n+1)

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As any housewives who has tried to keep order at the dinner table knows, there is far more to a family meal than food. Sociologist Michael Lewis has been studying 50 families to find out just how much more.

Lewis carried out his study by videotaping the families while they ate ordinary meals in their own homes. They found that parents with small families talk actively with each other and their children. But as the number of children gets larger, conversation gives way to the parents’ efforts to control the loud noise they make. That can have an important effect on the children. “In general the more question-asking the parents do, the higher the children’s IQ scores,” Lewis says. “And the more children there are, the less question-asking there is.”

The study also provides an explanation for why middle children often seem to have a harder time in life than their siblings. Lewis found that in families with three or four children, dinner conversation is likely to center on the oldest child, who has the most to talk about, and the youngest, who needs the most attention. “Middle children are invisible,” says Lewis. “When you see someone get up from the table and walk around during dinner, chances are it’s the middle child.” There is, however, one thing that stops all conversation and prevents anyone from having attention: “When the TV is on,” Lewis says, “dinner is nothing.”

小题1:The writer’s purpose in writing the text is to _________.

A.show the relationship between parents and children

B.teach parents ways to keep order at the dinner table

C.report on the findings of a study

D.give information about family problems小题2:By saying “Middle children are invisible” in paragraph 3, Lewis means that middle children _________.

A.have to help their parents to serve dinner

B.get the least attention from the family

C.are often not allowed to come to the dinner table

D.find it hard to get along well with other children小题3:Which of the following statements would the writer agree to?

A.Parents should talk to each of their children frequently.

B.It is a good idea to have the TV on during dinner.

C.It is important to have the right food for children.

D.Elder children should help the younger ones at dinner.

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上题子程序执行后,屏幕显示为 【7】

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2011年7月,住建部发布了“关于发布行业标准《建筑与市政工程施工观场专业人员职业标准》的公告”(第1059号),公告指出:该标准自2012年1月1日起实施。《建筑与市政工程施工现场专业人员职业标准》中规定,劳务员的主要工作职责之一是:“负责或监督劳务人员进出场及用工管理。”作为劳务员,对本岗位的工作职责必须掌握。请依据《建筑与市政工程施工现场专业人员职业标准》回答以下问题工程完工意味着工程验收合格()

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半夏鲜汁中的半夏蛋白具有

A.抑制早期妊娠作用

B.抑制中期妊娠作用

C.中期妊娠引产作用

D.早期妊娠引产作用

E.以上都不是

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