问题 选择题

下表是某同学整理的实验报告,其中错误的是(  )

实验内容加入试剂或方法
A鉴别(NH42SO4固体和K2SO4固体加熟石灰研磨
B鉴别羊毛纤维和涤纶抽丝灼烧
C鉴别黄金和黄铜观察颜色
D鉴别硬水和软水加肥皂水

A.A

B.B

C.C

D.D

答案

A、鉴别K2SO4和(NH42SO4时,钾离子和其它离子结合都能溶于水不产生明显特征,故鉴别除铵根离子即可,加熟石灰研磨产生具刺激性气味的氨气即为硫酸铵,此方法可行;

B、羊毛纤维与涤纶在燃烧时所产生的气味不同,羊毛纤维有焦羽毛味,故此方法可行;

C、黄金和黄铜均为金黄色固体,观察颜色的方法不可行;

D、区分硬水和软水加肥皂液时硬水的泡沫少软水泡沫多,故此方法可行.

故选C.

单项选择题
阅读理解

C

A blow-fly was looking for an ideal place like rotting meat to lay her eggs so that when her little babies were born, they could feed on the meat.

As she turned a corner in the grassland, she smelt something that smells like rotten meat in the air! With a great joy she landed on it and laid her eggs. She was happy that her children would have enough food to eat.

But the fly did not know she had made a great mistake. What she had sat upon was not meat but a flower, which smells badly. It is called a carrion flower. So, when the blow-fly’s eggs hatched and the little maggots(蛆)came out, they had nothing to eat. They died of starvation.

The carrion flower is one of the many flowers which send out dirty smells to attract flies. The Rafflesia stinks like rotting meat, while the tropical Lords and Ladies flower gives out a smell like rotting fish.

They do it for a special reason. These plants cannot move from their place. But it is important for the male cell of one plant to get in touch with the female cell of another plant. Once that is done, the seed of the plant will bloom and give birth to another plant.

The plant uses its stink to attract flies. As soon as the blow-fly sits on the follower, it is captured by the flower with strong hair. When the hair falls, the fly is free to fly- but it takes some pollen(花粉) with it. And goes and sits on another plant. The male cell of one plant meets the female cell of the other. The seed gets new life.

64. Why did the fly land on something smelly?

A. She was too careless before her bearing.       B. She liked the particular smell very much

C. She hoped to find some food for her babies.    D. She couldn’t find a better place for delivery.

65. The little maggots finally died because_________.

A. they were born too weak             B. they lacked food available

C. carrion flower were poisonous         D. their mother didn’t take care of them

66. Flowers like carrion flower and Rafflesia naturally smell terrible so that_________.

A. they need insects to spread their pollen     B. they succeed in producing more seeds

C. their seeds can be carried to other places    D. they can manage to absorb more nutrients

67. What is the best title of the text?

A. Dirty Tricks        B. Smelly Plants   C. A strange Flower   D. Secrets of Nature.