锆石极耐高温,其熔点达2750℃,并耐酸腐蚀。世界上有80%的锆石直接用于铸造、陶瓷

题型:单项选择题

问题:

锆石极耐高温,其熔点达2750℃,并耐酸腐蚀。世界上有80%的锆石直接用于铸造、陶瓷、玻璃工业以及制造耐火材料,少量的锆石用于铁合金、医药、油漆、制革、磨料、化工及核工业,极少量的锆石用于冶炼金属锆。含Zro265%~66%的锆石英砂因其耐熔性(熔点2500℃以上)而直接用做铸造厂铁金属的铸型材料。 这段话的主要目的是告诉我们( )。

A.锆石极耐高温

B.锆石的工业用途

C.锆石耐酸腐蚀

D.锆石性质特殊

考点:地方公务员行政职业能力测试四川省行政职业能力测验
题型:单项选择题
用水清洗一堆蔬菜,据科学测定,其效果如下:用x单位量的水清洗一次以后,蔬菜上残留的农药量与这次清洗前残留的农药量之比为f(x)=
1
1+x2

(1)因为f(0)=______,所以f(0)的实际意义是______(后一个处请选择下列之一);
A.表示没有用水清洗时,蔬菜上的农药量;
B.表示没有用水清洗时,蔬菜上的农药量没有变化;
C.表示没有用水清洗.
(2)现用a(a>0)单位量的水去清洗一堆蔬菜,方案一:用a单位量的水清洗一次;
方案二:把a单位量的水平均分成2份后清洗两次.试问:哪种方案比较好(即清洗后蔬菜上残留的农药量比较少)?请说明理由.
(为方便计算,可以假设清洗前蔬菜上的农药量为1,清洗后残留的农药量:方案一的记为W1,方案二的记为W2).
题型:单项选择题

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中的两项为多余选项。

If you do not use your arms or your legs for some time, they become weak; when you start using again, they slowly become strong again. Everybody knows this, and nobody would think of questioning the fact. ____小题1:____ When someone says that he has a good memory, he really means that he keeps his memory in practice by exercising it regularly, either consciously or unconsciously. When someone else says that his memory is poor, he really means that he does not give it enough opportunity to become strong. ____小题2:____ One of them exercises his arms and legs by playing tennis, while the other sits in a chair or a motor car all day.

If a friend complains that his arms are weak, we know that it is his own fault. ____小题3:____, many of us think that his parents are to blame, or that he is just unlucky, and few of us realize that it is just as much his own fault as if it was his arms or legs that were weak. Not all of us can become extremely strong or extremely clever; but all of us can, if we have ordinary bodies and brains, improve our strength and our memory by the same means––practice.

Have you ever noticed that people who cannot read or write usually have better memories than those who can? ____小题4:____ Of course, because those who cannot read or write have to remember things:they cannot write them down in a little notebook. They have to remember dates, time and prices, names, songs and stories; so their memory is the whole time being exercised.

____小题5:____, learn from the poor: practice remembering.

A.What do you think of it?

B.Yet many people do not seem to know that the memory works in the same way.

C.But if he tells us that he has a poor memory

D.So if you want a good memoryE. When someone else says that he is poor in the health

F. Why is this?

G. The position is exactly the same as that of two people.

题型:单项选择题

师生关系不仅影响我们的学习质量,而且影响我们的身心发展。

为了使自己健康成长,你认为我们应怎样与老师交往?

_______________________________________________________________________________

题型:单项选择题

一个群体中按血型、性别或职业等统计出来的数据属于计数资料。

题型:单项选择题

女性,42岁,乏力、面色苍白、尿色黄1年。重度贫血貌,巩膜轻度黄染,肝、脾肋下未触 及。血清总胆红素27μmol/L,非结合胆红素19μmol/L,肝功能正常。尿潜血(+++)。血红蛋白55g/L,白细胞3.5×109/L,平均红细胞体积70fl,血小板72×109/L。骨髓象:中幼+晚幼红细胞66%,网织红细胞9%。

下列哪项处理不合理

A.右旋糖酐

B.糖皮质激素

C.输洗涤红细胞

D.补充足够的铁剂

更多题库