刻度尺是测量____________的基本工具，左图所示的测量中，木块长度是____________厘米。

（1）“测平均速度”实验中已有的器材是小车，斜面、金属片，还缺少的器材是________和___________。
（2）根据图所示，填写下列表格。（保留两位有效数据）


（3）实验中为了方便计时，应使斜面的坡度较_______（填“大”或“小”）。

从物理学角度来看甲、乙是两种声音在同一个示波器上显示出来的波形，从图形可知图       是乐音的波形，图       是噪声的波形。
 

如图所示，将钢尺的一端紧压在桌面上，拨动伸出桌面的一端会听到声音，轻拨和重拨，则钢尺发出声音的 _______；显著改变刻度尺伸出桌面的长度，两次相同的力拨动，能够听出声音的_______发生了变化.

Grown-ups know that people and objects are solid. At the movies, we know that if we reach out to touch Tom Cruise, all we will feel is air. But does a baby have this understanding?
To see whether babies know objects are solid. T. Bower designed a method for projecting an optical illusion (视觉影像) of a hanging ball. His plan was to first give babies a real ball, one they could be expected to show surprised in their faces and movements. All the 16 to 24-week-old babies tested were surprised when they reached for the illusion and found that the ball was not there.
Grown-ups also have a sense of object permanence. We know that if we put a box in a room and lock the door, the box will still be there when we come back. But does a baby realize that a ball that rolls under a chair does not disappear and go to never-never land?
Experiments done by Bower suggest that babies develop a sense of object permanence when they are about 18 weeks old. In his experiments, Bower used a toy train that went behind a screen. When 16-week-old and 22-week-old babies watched the toy train disappear behind the left side of the screen, they looked to the right, expecting it to re-appear. If the experiment took the train off the table and lifted the screen, all the babies seemed surprised not to see the train. This seems to show that all the babies had a sense of object permanence. But the second part of the experiment showed that this was not really the case. The researcher substituted (替换) a ball for the train when it went behind the screen. The 22-week-old babies seemed surprised and looked back to the left side for the train. But the 16-week-old babies did not seem to notice the switch (更换). Thus, the 16-week-old babies seemed to have a sense of “something permanence,” while the 22-week-old babies had a sense of object permanence related to a particular object.
【小题1】The passage is mainly about         .

A．babies’ sense of sight	B．effects of experiments on babies
C．babies’ understanding of objects	D．different tests on babies’ feelings

【小题2】In Paragraph 3, “object permanence” means that when out of sight, an object            .

A．still exists

B．keeps its shape

C．still stays solid

D．is beyond reach

【小题3】What did Bower use in his experiments?

A．A chair

B．A screen

C．A film

D．A box

【小题4】Which of the following statements is true?

A．The babies didn’t have a sense of direction.

B．The older babies preferred toy trains to balls.

C．The younger babies liked looking for missing objects

D．The babies couldn’t tell a ball from its optical illusion.

Grown-ups know that people and objects are solid. At the movies, we know that if we reach out to touch Tom Cruise, all we will feel is air. But does a baby have this understanding?
To see whether babies know objects are solid. T. Bower designed a method for projecting an optical illusion (视觉影像) of a hanging ball. His plan was to first give babies a real ball, one they could be expected to show surprised in their faces and movements. All the 16 to 24-week-old babies tested were surprised when they reached for the illusion and found that the ball was not there.
Grown-ups also have a sense of object permanence. We know that if we put a box in a room and lock the door, the box will still be there when we come back. But does a baby realize that a ball that rolls under a chair does not disappear and go to never-never land?
Experiments done by Bower suggest that babies develop a sense of object permanence when they are about 18 weeks old. In his experiments, Bower used a toy train that went behind a screen. When 16-week-old and 22-week-old babies watched the toy train disappear behind the left side of the screen, they looked to the right, expecting it to re-appear. If the experiment took the train off the table and lifted the screen, all the babies seemed surprised not to see the train. This seems to show that all the babies had a sense of object permanence. But the second part of the experiment showed that this was not really the case. The researcher substituted (替换) a ball for the train when it went behind the screen. The 22-week-old babies seemed surprised and looked back to the left side for the train. But the 16-week-old babies did not seem to notice the switch (更换). Thus, the 16-week-old babies seemed to have a sense of “something permanence,” while the 22-week-old babies had a sense of object permanence related to a particular object.
【小题1】The passage is mainly about         .

A．babies’ sense of sight	B．effects of experiments on babies
C．babies’ understanding of objects	D．different tests on babies’ feelings

【小题2】In Paragraph 3, “object permanence” means that when out of sight, an object            .

A．still exists

B．keeps its shape

C．still stays solid

D．is beyond reach

【小题3】What did Bower use in his experiments?

A．A chair

B．A screen

C．A film

D．A box

【小题4】Which of the following statements is true?

A．The babies didn’t have a sense of direction.

B．The older babies preferred toy trains to balls.

C．The younger babies liked looking for missing objects

D．The babies couldn’t tell a ball from its optical illusion.

Grown-ups know that people and objects are solid. At the movies, we know that if we reach out to touch Tom Cruise, all we will feel is air. But does a baby have this understanding?
To see whether babies know objects are solid. T. Bower designed a method for projecting an optical illusion (视觉影像) of a hanging ball. His plan was to first give babies a real ball, one they could be expected to show surprised in their faces and movements. All the 16 to 24-week-old babies tested were surprised when they reached for the illusion and found that the ball was not there.
Grown-ups also have a sense of object permanence. We know that if we put a box in a room and lock the door, the box will still be there when we come back. But does a baby realize that a ball that rolls under a chair does not disappear and go to never-never land?
Experiments done by Bower suggest that babies develop a sense of object permanence when they are about 18 weeks old. In his experiments, Bower used a toy train that went behind a screen. When 16-week-old and 22-week-old babies watched the toy train disappear behind the left side of the screen, they looked to the right, expecting it to re-appear. If the experiment took the train off the table and lifted the screen, all the babies seemed surprised not to see the train. This seems to show that all the babies had a sense of object permanence. But the second part of the experiment showed that this was not really the case. The researcher substituted (替换) a ball for the train when it went behind the screen. The 22-week-old babies seemed surprised and looked back to the left side for the train. But the 16-week-old babies did not seem to notice the switch (更换). Thus, the 16-week-old babies seemed to have a sense of “something permanence,” while the 22-week-old babies had a sense of object permanence related to a particular object.
【小题1】The passage is mainly about         .

A．babies’ sense of sight	B．effects of experiments on babies
C．babies’ understanding of objects	D．different tests on babies’ feelings

【小题2】In Paragraph 3, “object permanence” means that when out of sight, an object            .

A．still exists

B．keeps its shape

C．still stays solid

D．is beyond reach

【小题3】What did Bower use in his experiments?

A．A chair

B．A screen

C．A film

D．A box

【小题4】Which of the following statements is true?

A．The babies didn’t have a sense of direction.

B．The older babies preferred toy trains to balls.

C．The younger babies liked looking for missing objects

D．The babies couldn’t tell a ball from its optical illusion.

20世纪40年代末，某地的植被遭到严重破坏，政府从70年代开始采取积极的植被恢复措施。主要方法是大面积飞播云南松种子，实施封山育林。从外表上看，这些恢复起来的植被覆盖很好，曾经被视为我国植被恢复成功的典范。但实际上却是“绿色沙漠”的例证．“绿色沙漠”是指大面积的人工树林，其构成树木种类单一，年龄和高矮比较接近，且十分密集，林下缺乏中间的灌木层和地表植被。为什么称之为“绿色沙漠”，请你说明理由：

20世纪40年代末，某地的植被遭到严重破坏，政府从70年代开始采取积极的植被恢复措施。主要方法是大面积飞播云南松种子，实施封山育林。从外表上看，这些恢复起来的植被覆盖很好，曾经被视为我国植被恢复成功的典范。但实际上却是“绿色沙漠”的例证．“绿色沙漠”是指大面积的人工树林，其构成树木种类单一，年龄和高矮比较接近，且十分密集，林下缺乏中间的灌木层和地表植被。为什么称之为“绿色沙漠”，请你说明理由：

20世纪40年代末，某地的植被遭到严重破坏，政府从70年代开始采取积极的植被恢复措施。主要方法是大面积飞播云南松种子，实施封山育林。从外表上看，这些恢复起来的植被覆盖很好，曾经被视为我国植被恢复成功的典范。但实际上却是“绿色沙漠”的例证．“绿色沙漠”是指大面积的人工树林，其构成树木种类单一，年龄和高矮比较接近，且十分密集，林下缺乏中间的灌木层和地表植被。为什么称之为“绿色沙漠”，请你说明理由：