问题 探究题

某同学想探究土壤湿度对蚯蚓生活的影响,未完成,请你接着做它。

(1)你认为他可在__________________________的环境中才能找到试验用的蚯蚓。

(2)按照科学实验的要求,他必须设计________实验,才更具有说服力。在这个实验中______________是变量,要控制好。

(3)你作出的假设是:________________________________________.

(4)请你设计一个实验来探究土壤湿度对蚯蚓的影响:(只写出具体操作步骤即可)

_____________________________________________________________________

(5)实施计划

(6)得出结论:_____________________________________________________。

(7)表达交流

答案

(1)潮湿、疏松、富含有机物(2)对照;土壤湿度(3)土壤湿度对蚯蚓的生活有影响(4)准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可.主要操作步骤:准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可.(6)蚯蚓喜欢生活在阴暗潮湿的环境.(7)略

题目分析:(1)从日常生活、生产实际或学习中发现与生物学相关的问题.蚯蚓可能在潮湿、疏松、富含有机物的环境找到;(2)按照科学实验的要求,他必须设计对照实验.对照实验是指在研究一种条件对研究对象的影响时,所进行的除了这种条件不同之外,其他条件都相同的实验.其中不同的条件就是实验变量.这样便于排除其他条件干扰实验,使实验更具有说服力.该实验的实验变量是土壤湿度(或水分);(3)作出假设:对提出问题作出肯定或否定的回答.此题的假设是土壤湿度对蚯蚓的生活有影响;(4)主要操作步骤:准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可.主要操作步骤:准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可;(6)蚯蚓喜欢生活在阴暗潮湿的环境。故答案为:(1)潮湿、疏松、富含有机物(2)对照;土壤湿度(3)土壤湿度对蚯蚓的生活有影响(4)准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可.主要操作步骤:准备一个盒子,底面铺上一层干土,在其中一半浇适量水,然后把10条形态大小相似的蚯蚓放在中间,盒子盖上盖子,几分钟后观察即可.(6)蚯蚓喜欢生活在阴暗潮湿的环境.(7)略

阅读理解

American schools begin in September after a long summer holiday.There are two terms in a school year,the first term is from September to January,and the second is from February to June.Most American children begin to go to school when they are five years old.Most students are seventeen or eighteen years old when they finish high school.

High school students take only four or five subjects(科目)each term.They usually go to the same class every day,and they have homework for every class.After class they do many interesting things.After high school,many students go to college.They can go to a small one or a large one.They usually have to give a lot of money.So many college students work after class to get the money for their studies.

小题1:Most American children go to school when they are _________ years old

A.four.

B.five .

C.six.

D.seven .小题2:High school students ______ after class .

A.do a lot of homework.

B.do many interesting things.

C.often sing songs.

D.do lots of reading.小题3:After high school , many students  _________ .

A.begin to work.

B.stay at home.

C.go to college.

D.visit their friends.小题4:Many college students work after class because _________

A.they want to get some money for their studies .

B.they don' t have anything to do .

C.their parents ask them for money.

D.their teachers ask them to do so .小题5:From the passage we know that in America a summer holiday begins in _________  .

A.January

B.September.

C.February

D.July

单项选择题