烟道挡板开度不合适也可能是导致加热炉炉膛温度高的原因之一。()

题型:判断题

问题:

烟道挡板开度不合适也可能是导致加热炉炉膛温度高的原因之一。()

考点:精细化工考试精细化工考试题库
题型:判断题

如图所示,下列实验操作与方法正确的是(  )

A.

检查容量瓶是否漏水的方法

B.

给溶液加热

C.

滴加液体

D.

过滤

题型:判断题

When 18th-century scientists first came across Australia’s platypus(鸭嘴兽), they thought it was a trick. It is not surprising that the platypus made people confused. This funny-looking animal has feet and is a kind of warm-blooded mammal.

While other mammals usually keep their blood at around 37 degrees, the platypus has a lower body temperature of 32 degrees. As to its appearance, the platypus’mouth is not really like ducks’at all; its mouth actually looks a bit soft. The platypus closes its eyes when swimming. It uses its mouth to pick up outside information made by the creatures underwater.

Strangest of all, the platypus is a mammal that can lay eggs. And there is only one other kind of mammal that can lay eggs, the echidna (针鼹鼠) of Australia. Both the platy-pus and the echidna lay soft-shelled eggs, and both feed their young with their own milk that comes out of their skin. These animals also walk in a way that is similar to crocodiles(鳄鱼), with legs on the sides of their bodies rather than under them.

Though pretty, in a special way, the platypus is actually one of the few mammals that are poisonous. A male platypus has knife-like bones on its back legs which have enough poison to kill a dog.

The platypus has the honor of being one of the oldest mammals in the world. Until the early 20th century, it was hunted for its fur, but the situation has changed. Although the platypus is easily affected by pollution, it is not under any immediate threat.

小题1: What can we learn about the platypus according to the text?

A.It has a lower body temperature than other mammals.

B.It only closes its eyes when underwater.

C.It’s the only poisonous mammal in the world.

D.It feeds its young on wild animal meat.小题2:Which of the following is NOT used as a comparison with the platypus in the text?

A.The crocodile.

B.The echidna.

C.The duck.

D.The dog.小题3:The following characteristics of the platypus have been described in the text EXCEPT ________.

A.its natural enemy

B.its appearance

C.its walking pose

D.its daily diet小题4:We can infer from the last paragraph that the platypus _______.

A.is hunted for its meat

B.is in danger of extinction

C.is endangered by air pollution

D.is well-protected now小题5:Which of the following would be the best title for this text?

A.Platypus, a Trick?

B.Platypus, the Only Warm-Blooded Mammal

C.The Characteristics of Platypus

D.The Strange Mammal —Platypus。

题型:判断题

设有关系模式W(C,P,S,G,T,R),其中各属性的含义是:C——课程,P——教师,S——学生,G——成绩,T——时间,R——教室,根据语义有如下的数据依赖集:

D=C→P,(S,C)→G,(T,R)→C,(T,P)→R,(T,S)→R。关系模式W的一个码(关键字)是 (1) ,W的规范化程度最高达到 (2)

2()

A.2NF

B.3NF

C.BCNF

D.4NF

题型:判断题

纳税人新购置车辆使用的,其车辆使用税的纳税义务发生时间为( )。

A.购置使用的当月起

B.购置使用的次月起

C.购置使用的当年起

D.购置使用的次年起

题型:判断题

进行气割作业时,在什么部位安装回火防止器?

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