问题 填空题

探究和分析.

使用显微镜观察的材料必须是薄而透明的原因.

(1)提出问题:使用显微镜观察的材料______?

(2)作出假设:用显微镜观察的材料______.

(3)实验:将树叶、树枝、手指、干报纸、湿报纸以及叶的下表皮等材料,放在显微镜下观察.

(4)实验现象:薄而透明的材料在显微镜下______(选填“能”或“不能”)被观察到,厚而不透明的材料在显微镜下______(选填“能”或“不能)被观察到.

(5)实验结论:______.

答案

答:(1)就是把要探究的问题设成疑问,便于针对问题研究.

    (2)依据客观事实和生活经验对所要研究的问题做一个假设,然后设计实验给与验证.

    (3)将树叶、树枝、手指、干报纸、湿报纸以及叶的下表皮等材料,放在显微镜下观察.由于树叶、树枝、手指、干报纸、湿报纸厚而不透明,显微镜视野一片黑暗;叶的下表皮比较薄而透明,所以在显微镜下能观察到.

    (4)由实验结果可知,显微镜所观察的物体必须薄、透明才能观察到,厚而不透明的材料在显微镜下不能被观察到.

    (5)实验结论通常是对作出的假设给予验证,然后给实验的结果得出结论.

故答案为:

(1)必须是薄而透明的吗?

(2)应该是薄而透明的

(4)能,不能

(5)用显微镜观察的材料必须是薄而透明的.

阅读理解

阅读理解

     My mother through her fine example instilled (慢慢灌输)within me the desire to help others. She

taught me to notice those whom others ignore.

     The railroad tracks (轨道) were within a mile of our house. Beggars frequently would knock at the

doors in our neighbourhood in summer asking for food. They were often turned away. Others simply

ignored the knocks.

     My mum always went to the door smiling. She would invite them to stay and have something to eat.

She would have me open up the card table and carry a chair out onto the covered side porch (走廊).

There was a nice view into the flower gardens, and it was cool even on the hottest days.

     She would bring a red and white tablecloth and set the table as carefully as she did for any company.

She would pour their coffee and pile their plates with food and dessert. Usually she sent a packed lunch

with them when they were ready to go, too.Sometimes she would take the newspapers to those who

asked about work.

     She listened to those who wanted to talk.She never asked what would lead them to be in this difficult

situation. It did not matter. She saw only the need. Some thought she should not extend this courtesy (礼貌). She would say, "In the depression (萧条时期) when my father was searching around for any work to

feed us, thoughtful people fed him. I am just repaying their kindness. I cannot offer them money, but I can

see they do not leave hungry and discouraged." My mum was quite a lady.

1. The writer's house was frequently visited by beggars because________.

A. they seemed to be very rich

B. his mother was known to be generous

C. they lived near a railway station

D. there was a railway near their house

2. How did the writer's mother treat beggars?

A. She was on guard against them.

B. She looked down upon them.

C. She respected them equally.

D. She took pride in them.

3. The writer's mother sometimes took out newspapers________.

A. for the beggars to kill time

B. to teach the beggars how to read

C. to help the beggars who asked about work

D. to help the beggars to find their families

4. Which of the following can make an explanation for the mother's attitude to beggars?

A. Her father was once helped by others.

B. Her father liked to help beggars.

C. She was once a beggar herself.

D. Her mother taught her to help beggars.

单项选择题 A3/A4型题